Question 3 - 15 marks This question is based on your work on MU123 up to and including Unit 5. In this question, you are asked to comment on a student's incorrect attempt at answering the question detailed below. The question (i) Simplify the following expression as far as possible, showing all your working: 5y - 10 + 3y + 42. (ii) Solve the following equation, showing all your working: (t - 7) = 33. The student's incorrect attempt: (i) Given: 5y-10+ 3y + 42 Group like terms: = 5y + 3y-10+42 Collect like terms: = By + 32 Subtract 32: -32 = By Divide By 8: - 4 =y The solution is y = -. (ii) Given: 2(t - 1) =33 Clear the fraction: 3(+ -35) =165 Multiply By 3: 3t -105 = 165 Add 105: 3t =210 Divide By 3: + =90 The solution is t = 90. (a) The student has made a mistake in both parts of their attempt. Identify these mistakes and explain, as if directly to the student, why, for each mistake, their reasoning is incorrect. [4] b) Write out your own solution to each part of the question, explaining your working. [6](c) The student decides to check if the solution they got to part (ii) of the question was correct using the following approach: Check: Substitute 90 for t: =(90- 1) = 33 Work out the Brackets: (83) = 33 24+9 Giving: 5 - =33 This is incorrect so the solution t = 90 is incorrect (1) Explain why the approach to checking that they have chosen is incorrect. [2] (2) Show how the student should have performed the check. [3] Question 4 - 25 marks This question is based on your work on MU123 up to and including Unit 5. (a) Simplify each of the following expressions as far as possible; multiply out any brackets, expand any algebraic fractions, and collect like terms together. Show your working. (i) 11(4 - 6t] (ii) 13 + m(12 -9m) - 12m [3] (ii) 14t - 7(9s - 7t) (iv) 9p(6 + 8p2) -4(9p - 8 + 6p3) 9x- + 27x - 45 (v) [4] 9x (b) Solve the following equations. Show your working and check that your answers are correct. (i) 15a - 9 = 27 + 9a [4] (ii) = -7 =4(y -10) [5] Question 5 - 5 marks A score out of 5 marks for good mathematical communication over the entire TMA will be recorded under Question 5. [5]