Answer
g =$\frac{2A}{h}-f$
Work Step by Step
The first step is to divide each side of the equation by h:
$\frac{A}{h}$=$\frac{f+g}{2}$
Next, multiply each side of the equation by 2 to get:
$\frac{2A}{h}$= f+g
Lastly, subtract f from both sides to get g by itself, giving you the answer:
$g=\frac{2A}{h}-f$