QUESTION 4 (a) ABC is a company that manufactures computer desk. The total costs (in RM'000) when x units of computer desk are produced is given by C(x) = 12x3 - 198x2 + 1080x Find the level of x that the cost is at the minimum. What is the minimum cost? (8 marks) (b) Smart Kitchen sells and two different sets of dinner during this COVID-19 pandemic. The choice of dinner sets are Set A for 3-4 persons and Set B is for 5-6 persons in a family. Given x denotes number of Set A and y denotes number of Set B, the total revenue R(x, y) and the total cost C(x, y), both in Ringgit Malaysia are as follows: R(x, y) = 120x + 110y C(x, y) = 16x2 - 16xy + 8y2 - 24x + 78y + 200 Find the number of each set of dinner sets that must be sold in order to maximise its profit. What is the maximum profit realizable? (12 marks) (c) Find the integral below: (x2 + 1 ) dx (2x3 + 6x) (5 marks) (Total: 25 marks)