function for cost of fence

Question

Hector is building a rectangular dog pen. One side will be the east side of his house, and the other three sides will be made of mesh fencing that costs $7.25 per foot. He wants the enclosed area to be 4000 square feet. He also needs 4 posts that are $8.50 each.

Let x be the side perpendicular to the house. Write a function C(x) for the cost of the materials for the pen in terms of x. Simplify the answer

Answer 1

C(x) = 7.25(2x + 4000/x) + 4(8.75)

= 14.5x + 29000/x + 35