a closed box has a fixed surface area A and a suqare base wide side X

Question

a) find the formula for its volume, v, as a function x
b) sketch the graph of v against x
c) find the max value of V

Answer 1

area= 2x^2+4xh

Volume= hx^2
h= (area-2x^2)/4x

volume= 1/4 (area-2x^2)x

Answer 2

is that the answer for a ?

Answer 3

Volume of the box is x^2h and if you plug in the value of h, you get,
V=1/4(Ax-2x^3)/x