A window has the shape of a square surmounted by an isosceles triangle. The sides of the square are length x. The The perimeter of the window is 90 inches. Thus, the perimeter of the triangle is x+2y. So, 90 inches = 3x+2y.

Question

(a) Write an equation for the area of the window in terms of x and y.
(b) Use the fact that the perimeter of the window is 90 inches to write the area as a function
of only x.
(c) In this situation, what is the largest that x can be? What is the smallest x can be?

THANK YOU FOR ANY AND ALL HELP!