ments 29. A pool complex is made up of a rectangular swimming pool with side lengths 2x m and y m attached to a o Yunkang Chen semi-circular spa of radius x m ym 2x m The perimeter of the pool complex is 100m. a. Express y in terms of x. b. Show that the surface area of the pool complex is given by 4 = 100.x - 7 ( 7 + 4 ).ments C. Find the value of x for which the surface area of the pool complex is a maximum. It is not necessary to find this maximum surface area. Yunkar Using the result from part b. or otherwise, explain why the value of x found in part c. gives a maximum rather than a minimum surface area