-g+F/A=h^3 for A Add g to each side: -g + g+F/A=h^3 + g Cancel the g's on the left side: F/A = h^3 + g Cross multiply: F = A(h^3 + g) Divide each side by (h^3 + g) F/(h^3 + g) = A(h^3 + g)/(h^3 + g) Cancel (h^3 + g) on the right side: A = F/(h^3 + g)