Answer
$\frac{-2x-h}{x^2(x+h)^2}$
Work Step by Step
Step 1. $f(x+h)=\frac{1}{(x+h)^2}$
Step 2. $f(x+h)-f(x)=\frac{1}{(x+h)^2}-\frac{1}{x^2}=\frac{x^2-(x^2+2xh+h^2)}{x^2(x+h)^2}=\frac{-2xh-h^2}{x^2(x+h)^2}$
Step 3. $\frac{f(x+h)-f(x)}{h}=\frac{-2x-h}{x^2(x+h)^2}$
