therefore 2hw + 2hl is the cost of the sides and 5wl is the cost of the base

therefore

total cost = 2hw + 2hl + 5wl --> min

and i want find the dimensions to minimize cost.

I know how to do problems like these ive done many, its just this one is somehow bothering me...

i need to solve for 1 variable then i have a formula with 2 variables.. then i take the partial derivatives to see if my dimensions that i find indeed minimize cost. but for some reason i cant even get past my total cost formula.... help please