Question 1 20 marks This question is based on your work on MU123 up to and including Unit 10. (a) This part of the question concerns the quadratic equation 222 62 +7 = 0. (i) Find the discriminant of the quadratic expression 2z 6x + 7. [2] (i) What does this discriminant tell you about the number of solutions of the equation 222 6z + 7 = 0? Explain your answer briefly. [2] (iii) What does this discriminant tell you about the graph of y = 22% 6z + 77 [1] (b) Figure 1 shows part of the graph of the quadratic function y = 2x2 + 2z + 4. (-1,0) (2,0) . Figure 1 (i) Explain why the graph of the quadratic function y = 2z% + 22 | 4 is n-shaped. [1] (ii) Write down the y-intercept. [1] (iii) Using information from the graph, find the equation of the axis of symmetry of the parabola given by y 2z2 + 2z + 4. [2] (iv) Use your answer to part (b)(iii) to find the coordinates of the vertex of the parabola given by y = 2z2 + 2z + 4. [2] (c) This part of the question concerns the quadratic function y::1:23:1:4. Write the quadratic expression z2 3z 4 in completed-square form, showing your working. Use the completed-square form from part (c)(i) to solve the equation 22 3z 4 - 0. Use the completed-square form from part (c)(i) to write down the coordinates of the vertex of the parabola y = z? 3z 4. Provide a sketch of the graph of the parabola y z2 3z 4 If you intend to go on to study more mathematics, then you are advised to sketch by hand for the practice. Whichever method you choose, you should refer to the graph-sketching strategy box in Subsection 2.4 of Unit 10 for information on how to sketch and label a graph correctly