I have an area A = 2500ft^{2 }of a rectangular fence

the area is found base * height

the base is X and height is H

Each fence post is $25; meaning $100 for all 4 of them

Only 3 of the sides are being fenced, X X and H

it costs $5 per ft on sides of X and $10 on H

C = cost

I am lost as to how to make a formula to tie all this information together. To make a formula in terms of C(x)=

H is something i made up to hold the place of Height the rest are given.