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Q1[5 marks]easyCh1 · Quadratics· The quadratic formulaAO2
A biologist is studying a population growth model that can be approximated by the quadratic equation 5x^2 - 7x + 1 = 0, where x represents a specific time parameter. The biologist needs to find the exact values of x when the population satisfies this condition.
(a) Solve the equation 5x^2 - 7x + 1 = 0 using the quadratic formula, giving your answers correct to 3 significant figures. [5]
Q2[8 marks]mediumCh1 · Quadratics· Solving more complex quadratic equationsAO1AO2
A mathematical function is defined as y = (x^2 - x)^2 - 8(x^2 - x) + 12. Understanding its roots and graphical behaviour is important in certain optimisation problems.
(a) Find the real roots of the equation (x^2 - x)^2 - 8(x^2 - x) + 12 = 0. [5]
(b) Sketch a possible graph of y = (x^2 - x)^2 - 8(x^2 - x) + 12, indicating the x-intercepts. [3]
Q3[9 marks]mediumCh1 · Quadratics· The quadratic formulaAO1AO2AO3
A student is investigating the number of real roots for different quadratic equations.
(a) Sketch the graph of a quadratic function that has no real roots. [3]
(b) Explain how the discriminant value relates to your sketch in part (a). [3]
(c) Calculate the discriminant for the equation x^2 + 2x + 5 = 0. [3]
Q4[7 marks]mediumCh1 · Quadratics· Completing the squareAO2
Completing the square can be used both to rewrite quadratic expressions and to solve quadratic equations by isolating the variable.
(a) Use the method of completing the square to express x^2 + 6x - 2 in the form (x + p)^2 + q. [4]
(b) Hence, solve the equation x^2 + 6x - 2 = 0, leaving your answers in surd form. [3]
Q5[12 marks]hardCh1 · Quadratics· Completing the squareAO1AO2AO3
Fig 1.1 shows the graph of a quadratic function given by y = ax^2 + bx + c. The curve represents the trajectory of a ball thrown into the air.
(a) Analyse Fig 1.1. State the coordinates of the vertex of the parabola. [4]
(b) Compare the completed square form y = a(x - h)^2 + k with the graph, and evaluate the values of a, h, and k for the function shown in Fig 1.1. [8]
Q6[10 marks]hardCh1 · Quadratics· The quadratic formulaAO1AO2
A civil engineer is designing a parabolic arch for a bridge. The shape of the arch can be modelled by a quadratic equation.
(a) Find the values of x that satisfy the equation (x - 1)^2 = 2x + 5, giving your answers correct to 2 decimal places. [6]
(b) Deduce the nature of the roots of the equation in part (a) based on your solutions. [4]
Q7[9 marks]mediumCh1 · Quadratics· Solving more complex quadratic equationsAO1AO2AO3
Fig 1.1 shows a graph of the function y = 2x - 7√x + 3.
(a) Solve the equation 2x - 7√x + 3 = 0, giving your answers in exact form. [7]
(b) Show that one of the solutions is extraneous if we do not consider the domain of √x to be restricted to the principal (positive) square root. [2]
Q8[5 marks]easyCh1 · Quadratics· Completing the squareAO1AO2
The method of completing the square is a powerful technique for rewriting quadratic expressions into a standard form that reveals important properties of the function.
(a) Express x^2 - 8x + 19 in the form (x + a)^2 + b, where a and b are constants to be found. [5]
Q9[4 marks]easyCh1 · Quadratics· The number of roots of a quadratic equationAO1AO2
The number of real roots of a quadratic equation can be determined by evaluating its discriminant. Consider the quadratic equation 3x^2 - 7x + 2 = 0.
(a) Determine the number of distinct real roots for this equation. [4]
Q10[6 marks]easyCh1 · Quadratics· Completing the squareAO1AO2
A quadratic function is given in the completed square form y = (x - h)^2 + k. Fig 1.2 shows the graph of such a function.
(a) Identify the values of h and k from the graph in Fig 1.2. [3]
(b) Explain how the vertex of a parabola relates to its completed square form. [3]
Q11[6 marks]easyCh1 · Quadratics· Solving simultaneous equations (one linear and one quadratic)AO1AO2
A line and a curve are defined by the equations y = 2x + 3 and y = x^2 + x - 1 respectively.
(a) Calculate the coordinates where the line y = 2x + 3 intersects the curve y = x^2 + x - 1. [6]
Q12[5 marks]easyCh1 · Quadratics· Solving more complex quadratic equationsAO1AO2
Q13[5 marks]easyCh1 · Quadratics· Maximum and minimum values of a quadratic functionAO1AO2
The height of a projectile, h metres, above the ground after t seconds is given by the expression h(t) = t^2 - 6t + 1.
(a) Express t^2 - 6t + 1 in the form (t + a)^2 + b. [3]
(b) State the minimum value of the expression and the value of t at which it occurs. [2]
Q14[7 marks]mediumCh1 · Quadratics· Solving quadratic equations by factorisationAO1AO2
A metal plate has an area that can be modelled by a quadratic expression. Understanding its factors is important for its design.
(a) Find two linear factors of the expression 3x^2 - 10x - 8. [4]
(b) Hence, solve the equation 3x^2 - 10x - 8 = 0. [3]
Q15[7 marks]mediumCh1 · Quadratics· Solving simultaneous equations (one linear and one quadratic)AO1AO2
Fig 1.1 shows the graph of a straight line and a parabola. The equation of the line is y = x + 1 and the equation of the parabola is y = x^2 - 3x + 4.
(a) Find the coordinates of the points of intersection of the line and the curve shown in Fig 1.1. [5]
(b) Show that the x-coordinates of these points of intersection satisfy the equation x^2 - 4x + 3 = 0. [2]
Q16[10 marks]hardCh1 · Quadratics· Solving simultaneous equations (one linear and one quadratic)AO1AO2
A straight line with equation y = kx + 2 is tangent to the curve y = x^2 - 3x + 6.
(a) Determine the values of the constant k for which the line is tangent to the curve. [6]
(b) For the smaller value of k found in part (a), find the coordinates of the point of tangency. [4]
Q17[6 marks]easyCh1 · Quadratics· Maximum and minimum values of a quadratic functionAO1AO2
A parabolic arch is modelled by the curve y = 3x^2 + 18x - 10.
(a) Find the coordinates of the turning point of the curve y = 3x^2 + 18x - 10. [3]
(b) Sketch the curve, clearly showing the turning point and y-intercept. [3]
Q18[5 marks]easyCh1 · Quadratics· The number of roots of a quadratic equationAO1AO2
Fig 1.1 shows the graph of a quadratic function y = f(x).
(a) State the number of real roots for the quadratic function y = f(x) shown in Fig 1.1. [3]
(b) Identify the sign of the discriminant for the quadratic function shown in Fig 1.1. [2]
Q19[10 marks]hardCh1 · Quadratics· Completing the squareAO2AO3
A student is analysing the trajectory of a projectile and models its height using a quadratic equation. To understand the vertex of the trajectory, the student needs to express the equation in completed square form.
(a) Show that the equation 2x^2 - 10x + 11 = 0 can be written in the form 2(x - p)^2 + q = 0, stating the values of p and q. [6]
(b) Determine the exact solutions to the equation 2x^2 - 10x + 11 = 0 using the completed square form. [4]
Q20[10 marks]hardCh1 · Quadratics· Solving more complex quadratic equationsAO1AO2
A scientist is modelling the population growth of a certain bacteria culture, where the number of bacteria at time x (in hours) is given by an equation involving powers of 2.
(a) Solve the equation 2^(2x) - 9(2^x) + 8 = 0. [7]
(b) Explain why there are fewer solutions for x than expected for a standard quadratic equation. [3]
Q21[9 marks]mediumCh1 · Quadratics· The quadratic formulaAO1AO2
Engineers often use graphical methods to find approximate solutions to equations before carrying out precise calculations. Fig 1.1 shows the graph of the function y = x^2 - 2x - 4.
(a) Use the graph in Fig 1.1 to estimate the roots of the quadratic equation x^2 - 2x - 4 = 0. [4]
(b) Verify your estimates from part (a) by solving the equation x^2 - 2x - 4 = 0 using the quadratic formula, giving your answers correct to 1 decimal place. [5]
Q22[9 marks]mediumCh1 · Quadratics· Solving simultaneous equations (one linear and one quadratic)AO1AO2
A line and a circle are represented by the equations 3x + y = 7 and x^2 + y^2 = 13 respectively.
(a) Find the coordinates of the points of intersection of the line and the circle. [6]
(b) Plot the line and the circle on a coordinate grid, indicating the points of intersection. [3]
Q23[12 marks]hardCh1 · Quadratics· Solving more complex quadratic equationsAO1AO2
In a study of radioactive decay, the remaining amount of a substance at time x (in years) can be modelled by an equation that involves powers of 3.
(a) Solve the equation 3^(2x+1) - 28(3^x) + 9 = 0. [8]
(b) Analyse how the structure of the equation in part (a) allows it to be transformed into a quadratic form. [4]
Q24[11 marks]hardCh1 · Quadratics· Solving simultaneous equations (one linear and one quadratic)AO1AO2
A straight line with equation y = 3x + c is considered in relation to a quadratic curve with equation y = x^2 - 5x + 10.
(a) Determine the range of values for 'c' such that the line y = 3x + c does not intersect the curve y = x^2 - 5x + 10.
[7]
(b) Discuss the implications of a negative discriminant in this context.
[4]
Q25[7 marks]mediumCh1 · Quadratics· The quadratic formulaAO2AO3
An engineer is designing a parabolic antenna dish, and the cross-section can be modelled by a quadratic equation. To understand the properties of the curve, it is important to know if it intersects the x-axis and how many times.
(a) Calculate the discriminant of the quadratic equation 3x^2 - 5x - 2 = 0. [4]
(b) Determine the number of real roots for the equation 3x^2 - 5x - 2 = 0, justifying your answer. [3]
Q26[8 marks]mediumCh1 · Quadratics· Completing the squareAO2
Completing the square is a versatile algebraic technique that allows us to find the vertex and minimum/maximum values of quadratic functions.
(a) Express 3x^2 + 18x + 10 in the form a(x + b)^2 + c, where a, b and c are constants to be found. [5]
(b) Find the minimum value of the quadratic function 3x^2 + 18x + 10. [3]
Q27[6 marks]easyCh1 · Quadratics· Solving more complex quadratic equationsAO1AO2
A mathematical model for a physical phenomenon involves fractional powers of a variable x. To understand this model, it is necessary to solve the following equation.
(a) Determine the values of x that satisfy the equation x^(2/3) - 7x^(1/3) + 12 = 0. [6]
Q28[10 marks]hardCh1 · Quadratics· Solving quadratic equations by factorisationAO1AO2
When solving quadratic equations, it is crucial to ensure all possible solutions are found. Consider the equation 6x^2 + 5x = 4.
(a) Find the values of x that satisfy the equation 6x^2 + 5x = 4. [6]
(b) Discuss the common misconception of dividing by x when solving equations of this type and explain why it can lead to a loss of solutions. [4]
Q29[8 marks]mediumCh1 · Quadratics· Completing the squareAO2AO3
A parabolic archway is designed such that its shape can be modelled by the equation y = x^2 - 4x + 1. The architect needs to visualise this curve and identify its key features.
(a) Sketch the graph of y = x^2 - 4x + 1, clearly labelling the vertex and the y-intercept. [5]
(b) State the equation of the line of symmetry for this graph. [3]
Q30[8 marks]mediumCh1 · Quadratics· Solving simultaneous equations (one linear and one quadratic)AO1AO2
Fig 1.1 shows the graphs of a straight line and a quadratic curve. The straight line has the equation y = 3x - 1 and the curve has the equation y = 2x^2 - x + 2.
(a) Find the values of x and y that satisfy the simultaneous equations.
[6]
(b) Explain the geometric meaning of your solutions.
[2]
Q31[7 marks]mediumCh1 · Quadratics· Maximum and minimum values of a quadratic functionAO1AO2
The path of a ball thrown into the air can be modelled by the quadratic function f(x) = -2x^2 - 8x + 5, where f(x) is the height of the ball and x is the horizontal distance from the thrower. The graph of this function is shown in Fig 1.1.
(a) Find the maximum or minimum value of the function f(x) = -2x^2 - 8x + 5 and the x-coordinate where it occurs. [5]
(b) Identify whether it is a maximum or minimum value. [2]
Q32[12 marks]hardCh1 · Quadratics· Maximum and minimum values of a quadratic functionAO1AO2AO3
The general form of a quadratic function is y = ax^2 + bx + c.
(a) Derive the formula for the x-coordinate of the vertex of a parabola y = ax^2 + bx + c using the method of completing the square. [6]
(b) Evaluate the maximum value of the function h(x) = -3x^2 + 12x - 5 using the derived formula. [3]
(c) Compare the efficiency of finding the vertex using the derived formula versus directly completing the square for a given quadratic. [3]
Q33[6 marks]mediumCh1 · Quadratics· The number of roots of a quadratic equationAO1AO2
For a quadratic equation, the nature of its roots depends on the value of its discriminant. Consider the equation kx^2 + 6x + 2 = 0, where k is a constant.
(a) Find the set of values of k for which the equation has two distinct real roots. [6]
Q34[6 marks]mediumCh1 · Quadratics· The number of roots of a quadratic equationAO1AO3
Fig 1.4 shows the graph of a quadratic function y = ax^2 + bx + c.
(a) Interpret the meaning of the discriminant for the parabola shown in Fig 1.4. [3]
(b) Explain how changing the constant term of the quadratic function in Fig 1.4 might affect the number of real roots. [3]
Q35[7 marks]mediumCh1 · Quadratics· Solving more complex quadratic equationsAO1AO2
An algebraic expression is given by (x + 1)^2 + 3(x + 1) - 10 = 0.
(a) Find all real solutions to the equation (x + 1)^2 + 3(x + 1) - 10 = 0.
[5]
(b) Verify one of your solutions by substituting it back into the original equation.
[2]
Q36[8 marks]mediumCh1 · Quadratics· The quadratic formulaAO1AO2
A student is asked to solve a quadratic equation as part of a larger problem involving projectile motion.
(a) Solve the equation 2x^2 + 4x - 3 = 0, giving your answers in exact surd form. [5]
(b) Explain why factorisation might not be the preferred method for solving this equation. [3]
Q37[10 marks]hardCh1 · Quadratics· Maximum and minimum values of a quadratic functionAO1AO2AO3
The cost of producing a certain item, g(x) (in hundreds of dollars), depends on the number of items produced, x (in thousands), according to the function g(x) = x^2 - 4x + 7. The production is limited to a domain of -1 ≤ x ≤ 5. The graph of this function is shown in Fig 1.2.
(a) Determine the range of the function g(x) = x^2 - 4x + 7 for the domain -1 ≤ x ≤ 5. [6]
(b) Discuss how the restricted domain affects finding the maximum and minimum values. [4]
The profit, P, from selling x units of a product is modelled by a quadratic expression. Consider a related problem involving the inequality (x - 1)(x + 3) ≥ x + 3.
(a) Determine the set of values of x for which (x - 1)(x + 3) ≥ x + 3. [6]
(b) Explain how you would use a sign diagram to verify your answer for part (a). [4]
A projectile is launched from a platform, and its height h (in metres) at time t (in seconds) is modelled by a quadratic expression. Consider a related mathematical problem involving an inequality.
(a) Solve the inequality (x + 2)^2 > 4x + 7. [6]
(b) Discuss common student misconceptions when solving quadratic inequalities, particularly regarding division by variables or negative numbers. [4]
A manufacturer is designing a square plate for a new product. The area of the plate must be less than 9 units squared. Let x be the side length of the square plate.
Find the range of values of x for which x^2 - 9 < 0.
The height of a projectile, h metres, above the ground at time t seconds is modelled by a quadratic function. Consider a similar quadratic relationship given by y = 3x^2 + 10x - 8.
(a) Find the range of values of x for which 3x^2 + 10x ≤ 8. [4]
(b) Sketch the graph of y = 3x^2 + 10x - 8, clearly indicating the x-intercepts. [3]
Fig 1.5 shows the graph of a quadratic function y = f(x).
(a) Use the graph in Fig 1.5 to determine the range of x for which the function y = f(x) is positive (y > 0). [4]
(b) Determine the equation of the line of symmetry for the parabola shown. [3]
(c) State whether the vertex is a maximum or minimum point. [2]
Q43[8 marks]mediumCh1 · Quadratics· Maximum and minimum values of a quadratic functionAO1AO2AO3
A farmer wants to build a rectangular enclosure for his animals. He has 100 metres of fencing available.
(a) Calculate the dimensions of the rectangular enclosure that maximises its area. [6]
(b) Interpret the meaning of the maximum area in the context of the problem. [2]
Q44[8 marks]mediumCh1 · Quadratics· Solving quadratic equations by factorisationAO1AO2
An engineer is analysing the displacement of a component, which is described by the quadratic expression 4x^2 - 12x.
(a) Determine the values of x for which 4x^2 - 12x = 0. [5]
(b) Show that x = 0 is a valid solution to the equation. [3]
Q45[7 marks]mediumCh1 · Quadratics· Solving quadratic equations by factorisationAO1AO2
Consider the quadratic function y = x^2 - x - 6.
(a) Draw the graph of y = x^2 - x - 6 for x values from -3 to 4, labelling the x-intercepts and y-intercept. [4]
(b) From your graph, solve the equation x^2 - x - 6 = 0. [3]
Q46[6 marks]easyCh1 · Quadratics· Solving quadratic equations by factorisationAO1AO2
A scientist is analysing experimental data which produces a parabolic trend. Fig 1.2 shows the graph of a quadratic function f(x).
(a) Fig 1.2 shows the graph of a quadratic function. Identify the roots of the equation f(x) = 0 from the graph. [3]
(b) Explain how you would factorise the quadratic expression corresponding to this graph, given its roots. [3]
Q47[5 marks]easyCh1 · Quadratics· Solving quadratic equations by factorisationAO1AO2
A student is solving a quadratic equation as part of a larger problem.
(a) Solve the quadratic equation 2x^2 + 7x - 15 = 0 by factorisation. [5]
Q48[6 marks]easyCh1 · Quadratics· Solving quadratic equations by factorisationAO1AO2
A gardener is designing a rectangular flower bed. The length is (x + 3) metres and the width is (x - 5) metres. The area of the flower bed is 9 square metres.
(a) Solve the equation (x + 3)(x - 5) = 9 by first expanding and then factorising. [6]
A gardener is designing a rectangular flower bed. The area of the flower bed must satisfy certain conditions related to its length, x metres.
(a) Solve the quadratic inequality 2x^2 - 5x - 3 > 0. [3]
(b) Express your answer in set notation. [2]
The trajectory of a ball thrown into the air can be modelled by a quadratic function. Fig 1.1 shows the graph of a quadratic function y = x^2 - 2x - 3.
(a) Use the graph in Fig 1.1 to find the values of x for which x^2 - 2x - 3 < 0. [4]
(b) State the coordinates of the vertex of the parabola shown. [2]
(c) Deduce the range of values of x for which x^2 - 2x - 3 > 5. [2]
Q51[12 marks]hardCh1 · Quadratics· Intersection of a line and a quadratic curveAO2AO3
Fig 1.1 shows the graph of a line and a curve, representing the path of a moving object and a boundary, respectively.
(a) Use Fig 1.1 to estimate the coordinates of the points of intersection of the line y = -x + 4 and the curve y = x^2 - 2x + 1. [4]
(b) Verify your estimates by solving the equations algebraically. [5]
(c) Estimate the range of x values for which the curve is below the line. [3]
Q52[10 marks]hardCh1 · Quadratics· The number of roots of a quadratic equationAO1AO2AO3
The nature of the roots of a quadratic equation is determined by its discriminant. Consider the equation (p + 1)x^2 + 4px + 9 = 0, where p is a constant.
(a) Show that the equation has no real roots if p satisfies 9p^2 - 9p + 9 < 0. [5]
(b) Find the range of values of p for which the equation has two equal real roots. [5]
Q53[8 marks]mediumCh1 · Quadratics· Intersection of a line and a quadratic curveAO2AO3
Consider the line y = x - 3 and the curve y = 2x^2 + 3x - 1.
(a) Determine the number of points of intersection between the line and the curve. [5]
(b) Sketch the line and the curve on the same axes, showing their relative positions. [3]
Q54[7 marks]mediumCh1 · Quadratics· The number of roots of a quadratic equationAO1AO2
A quadratic equation models the height of a ball thrown vertically upwards. Consider the equation 2x^2 - 5x + c = 0, where x represents time and c is a constant related to the initial height.
(a) Determine the condition for the equation 2x^2 - 5x + c = 0 to have no real roots. [4]
(b) Illustrate this condition graphically by sketching a parabola that satisfies it. [3]
Q55[7 marks]mediumCh1 · Quadratics· The number of roots of a quadratic equationAO1AO2
The number of real roots of a quadratic equation relates to how its graph intersects the x-axis. Consider the equation x^2 + (m - 2)x + 4 = 0.
(a) Determine the value of m for which the equation has exactly one real root. [4]
(b) Explain the geometric significance of having exactly one real root for a quadratic equation. [3]
Q56[8 marks]mediumCh1 · Quadratics· Intersection of a line and a quadratic curveAO2AO3
A designer is modelling a parabolic arch for a bridge and a horizontal support beam. The arch is represented by the curve y = (x - 1)^2 + 2, and the support beam is represented by the line y = 4.
(a) Find the coordinates of the points where the line y = 4 intersects the curve y = (x - 1)^2 + 2. [5]
(b) Calculate the distance between these two points of intersection. [3]
Q57[11 marks]hardCh1 · Quadratics· Intersection of a line and a quadratic curveAO1AO2
A line and a curve are defined by the equations y = 3x + c and y = x^2 - x + 4, where c is a constant.
(a) Find the values of c for which the line y = 3x + c is a tangent to the curve y = x^2 - x + 4. [5]
(b) Show that for these values of c, there is only one point of intersection. [3]
(c) Deduce the coordinates of the point of tangency for one of the values of c found in part (a). [3]
Q58[9 marks]mediumCh1 · Quadratics· Intersection of a line and a quadratic curveAO1AO2
The trajectory of a projectile can be modelled by a quadratic curve, and a laser beam follows a straight line path. Consider a scenario where a laser beam given by the equation y = kx - 2 interacts with a parabolic trajectory given by the equation y = x^2 + 2x + 3.
(a) Find the range of values of k for which the line y = kx - 2 does not intersect the curve y = x^2 + 2x + 3. [6]
(b) Interpret your answer geometrically in terms of the positions of the line and the curve. [3]
Q59[6 marks]easyCh1 · Quadratics· Intersection of a line and a quadratic curveAO2
A straight line and a quadratic curve are given by the equations y = 2x + 1 and y = x^2 - 3x + 5 respectively.
(a) Find the coordinates of the points of intersection of the line y = 2x + 1 and the curve y = x^2 - 3x + 5. [6]
Q60[9 marks]mediumCh1 · Quadratics· Intersection of a line and a quadratic curve
Fig 1.2 shows a parabola y = x^2 - 4 and a straight line y = 2x - 1.
(a) State the y-intercept of the straight line. [2]
(b) Determine the coordinates of the vertex of the parabola by completing the square for y = x^2 - 4. [3]
(c) Calculate the area of the triangle formed by the two intersection points and the y-intercept of the line. [4]
Q61[9 marks]mediumCh1 · Quadratics· The number of roots of a quadratic equation
Fig 1.4 shows six graphs of quadratic functions, labelled A to F.
(a) Identify which graph represents a quadratic equation with two equal real roots. [2]
(b) Deduce the sign of the discriminant for graph C and explain your reasoning. [3]
(c) Determine the values of m for which the equation 2x^2 + 4x + m = 0 has no real roots, referring to similar graphs in the figure. [4]
Q62[4 marks]easyCh1 · Quadratics· Maximum and minimum values of a quadratic function
Fig 1.2 shows two parabolas on the same axes.
(a) Read the coordinates of the vertex for the inverted U-shaped parabola.
[2]
(b) State whether the U-shaped parabola has a maximum or minimum value, and give this value.
[2]
Q63[11 marks]hardCh1 · Quadratics· The number of roots of a quadratic equation
Fig 1.3 shows six graphs of quadratic functions, labelled A to F.
(a) Classify the nature of the roots for graph A and graph F, referring to their intersections with the x-axis. [3]
(b) Explain why the discriminant is zero for graph B, given that its equation is y = (x - 3)^2. [4]
(c) Derive the condition for the line y = mx + c to be tangent to the parabola y = x^2. [4]
Q64[9 marks]mediumCh1 · Quadratics· The number of roots of a quadratic equation
Fig 1.1 shows six graphs of quadratic functions, labelled A to F.
(a) State the number of real roots for:
(i) Graph A
(ii) Graph C
(b) Interpret the graphical representation of two distinct real roots, referring to specific examples from Fig 1.1.
(c) The quadratic equation x^2 - 6x + k = 0 represents a parabola similar to Graph A. Find the range of values for k such that this equation has two distinct real roots.
Q65[10 marks]hardCh1 · Quadratics· Intersection of a line and a quadratic curve
Fig 1.1 shows a parabola and a straight line on the same axes.
(a) Derive the equation of the parabola in the form y = ax^2 + bx + c, given its vertex and one x-intercept. [4]
(b) Solve the simultaneous equations y = x^2 - 4 and y = 2x - 1 algebraically. [3]
(c) Interpret the significance of the solutions found in part (b) with reference to the diagram. [3]
Q66[5 marks]easyCh1 · Quadratics· Solving quadratic equations by factorisation
Fig 1.1 shows the graph of the quadratic function y = x^2 - 5x - 14.
(a) Identify the values of x where the parabola intersects the x-axis.
[2]
(b) Solve the equation x^2 - 5x - 14 = 0 by factorisation, and state the roots.
[3]
Fig 1.3 shows a U-shaped parabola representing the function y = x^2 - 5x - 14.
(a) Identify the x-intercepts of the parabola shown in the figure.
(b) Write down the equation of the parabola in factored form, given that its y-intercept is -14.
(c) Solve the inequality x^2 - 5x - 14 > 0 using the information from the graph.
Fig 1.4 shows a U-shaped parabola with equation y = x^2 - 5x - 14.
(a) Read the x-intercepts of the parabola y = x^2 - 5x - 14 from the graph.
[2]
(b) Determine the values of x for which the function y = x^2 - 5x - 14 is positive.
[3]
(c) Sketch a graph of y = (x+2)(x-7) and indicate the region where y < 0.
[3]
Q69[4 marks]easyCh1 · Quadratics· Solving quadratic equations by factorisation
Fig 1.3 shows the graph of the quadratic function y = x^2 - 5x - 14.
(a) Read the x-intercepts of the parabola from the graph. [2]
(b) Factorise the quadratic expression x^2 - 5x - 14 using the x-intercepts found in part (a). [2]
Fig 1.4 shows the graph of the quadratic function y = x^2 - 5x - 14.
(a) Identify the x-coordinates where the parabola intersects the x-axis.
[2]
(b) Determine the range of x for which the quadratic function is negative (y < 0).
[3]
(c) Deduce the solution to the inequality (x+2)(x-7) ≥ 0, referencing the graph.
[4]
Fig 1.3 shows the graph of the quadratic function y = x^2 - 5x - 14.
(a) Identify the roots of the quadratic equation x^2 - 5x - 14 = 0 from the graph.
[2]
(b) Determine the range of x-values for which the curve y = x^2 - 5x - 14 is below the x-axis.
[3]
(c) Sketch a similar parabola for y = -(x + 2)(x - 7) and state the range of x for which y > 0.
[3]
Fig 1.4 shows a U-shaped parabola with the equation y = x^2 - 5x - 14.
(a) Read the y-intercept of the parabola from the diagram. [2]
(b) Determine the coordinates of the minimum point of the parabola. [3]
(c) Find the range of x for which x^2 - 5x - 14 < 0. [3]
Q73[11 marks]hardCh1 · Quadratics· The number of roots of a quadratic equation
Fig 1.1 shows six graphs of quadratic functions, labelled A to F.
(a) Identify which graphs represent quadratic equations with no real roots, and state the characteristic of these graphs that indicates this. [3]
(b) Explain the significance of the point of tangency on the x-axis for graphs B and E in relation to their discriminants. [4]
(c) Find the value of k for which the equation x^2 + kx + 9 = 0 has two equal real roots, similar to graph B (but shifted). [4]
Q74[5 marks]mediumCh1 · Quadratics· Completing the square
Fig 1.2 shows two parabolas on the same axes.
(a) Identify the coordinates of the vertex of the inverted U-shaped parabola.
(b) Write the equation of the inverted U-shaped parabola in the form y = a(x + b)^2 + c, given its vertex is (1, 3) and it crosses the y-axis at (0, 2).
Q75[12 marks]hardCh1 · Quadratics· The number of roots of a quadratic equation
Fig 1.4 shows six graphs of quadratic functions, labelled A to F.
(a) Analyse the relationship between the discriminant (b^2 - 4ac) and the position of the parabolas relative to the x-axis for graphs A, B, and C.
[4]
(b) Deduce the sign of the coefficient of x^2 for graph D and explain your reasoning.
[3]
(c) Find the possible values of k for the quadratic equation x^2 - 4x + k = 0, such that its graph would resemble graph B.
[5]
Q76[8 marks]mediumCh1 · Quadratics· Intersection of a line and a quadratic curve
Fig 1.1 shows a parabola with equation y = x^2 - 4 and a straight line with equation y = 2x - 1 on the same set of axes.
(a) Identify the y-intercept of the parabola.
[2]
(b) Determine the gradient of the straight line using the two intersection points of the line and the parabola.
[3]
(c) Calculate the value of y for the parabola when x = 1, and verify it matches the line's y-value at x=1.
[3]
Q77[9 marks]mediumCh1 · Quadratics· Intersection of a line and a quadratic curve
Fig 1.1 shows a parabola with equation y = x^2 - 4 and a straight line.
(a) State the equation of the straight line shown in the figure.
[2]
(b) Calculate the y-coordinate of the point on the parabola where x = 0.
[3]
(c) Find the x-coordinates of the intersection points by solving the equations simultaneously, and compare your findings with the diagram.
[4]
Q78[8 marks]mediumCh1 · Quadratics· Maximum and minimum values of a quadratic function
Fig 1.2 shows two parabolas on the same axes.
(a) Identify the coordinates of the turning point for the U-shaped parabola. [2]
(b) Determine the equation of the U-shaped parabola in the form y = x^2 + bx + c, given its vertex and y-intercept. [3]
(c) The inverted U-shaped parabola has the equation y = -(x - 1)^2 + 3. Calculate the y-coordinate of this parabola when x = 0, and verify it matches the diagram. [3]
Q79[10 marks]hardCh1 · Quadratics· Maximum and minimum values of a quadratic function
Fig 1.3 shows two parabolas on the same axes.
(a) Determine the equation of the line of symmetry for the U-shaped parabola.
[3]
(b) Formulate the equation of the inverted U-shaped parabola in the form y = a(x + b)^2 + c, given its vertex and y-intercept.
[4]
(c) Explain how the sign of the coefficient of x^2 determines whether a parabola has a maximum or minimum point.
[3]
Q80[10 marks]hardCh1 · Quadratics· The number of roots of a quadratic equation
Fig 1.4 shows six graphs of quadratic functions (A to F).
(a) Match each graph from Row 1 (A, B, C) to the correct condition for its discriminant (Δ > 0, Δ = 0, Δ < 0).
(b) Explain how the number of x-intercepts relates to the nature of the roots for graph C.
(c) Determine the value of c for graph B, given its equation is y = (x - 3)^2 + c and it touches the x-axis at x = 3.
Q81[5 marks]mediumCh1 · Quadratics· Completing the square
Fig 1.2 shows two parabolas on the same axes.
(a) Estimate the minimum value of the U-shaped parabola from the graph.
[2]
(b) Express the equation of the U-shaped parabola in the form (x+q)^2+r, given its minimum point is (-2, -4).
[3]
Q82[10 marks]hardCh1 · Quadratics· Solving more complex quadratic equations
Fig 1.4 shows two parabolas on the same axes.
(a) Deduce the equation of the line of symmetry for the U-shaped parabola.
(b) Formulate the equation of the inverted U-shaped parabola, given its vertex (1, 3) and y-intercept (0, 2), in the form y = ax^2 + bx + c.
(c) The equation of the U-shaped parabola is y = x^2 + 4x. Solve the equation formed by setting this quadratic function equal to the equation you found in part (b), to find their points of intersection, if any.
Q83[5 marks]easyCh1 · Quadratics· Intersection of a line and a quadratic curve
Fig 1.1 shows a parabola with equation y = x^2 - 4 and a straight line with equation y = 2x - 1.
(a) Read the coordinates of the two points of intersection from the graph.
(b) Verify algebraically that one of the points read in part (a) satisfies both equations y = x^2 - 4 and y = 2x - 1.
Q84[10 marks]hardCh1 · Quadratics· Intersection of a line and a quadratic curve
Fig 1.2 shows a parabola with equation y = x^2 - 4 and a straight line with equation y = 2x - 1.
(a) Determine the equation of the line passing through the two intersection points identified in Fig 1.2.
[3]
(b) Formulate a single quadratic equation by equating the expressions for y, and show that its discriminant is positive.
[4]
(c) Explain the geometric interpretation of a positive discriminant in the context of a line intersecting a parabola.
[3]
Q85[9 marks]mediumCh1 · Quadratics· Maximum and minimum values of a quadratic function
Fig 1.3 shows two parabolas on the same axes.
(a) Read the coordinates of the minimum point of the U-shaped parabola and the maximum point of the inverted U-shaped parabola.
[2]
(b) Express the equation of the U-shaped parabola in the form y = p(x+q)^2+r, given its vertex and y-intercept.
[4]
(c) Compare the y-intercepts of both parabolas as shown in the diagram.
[3]
Q86[6 marks]mediumCh1 · Quadratics· Maximum and minimum values of a quadratic function
Fig 1.2 shows two parabolas on the same set of axes.
(a) Identify the coordinates of the minimum point of the U-shaped parabola.
(b) Determine the equation of the line of symmetry for the inverted U-shaped parabola.
(c) State the y-intercept for the U-shaped parabola.