Answer
$-\frac{2x+h}{x^{2}(x+h)^{2}}$
Work Step by Step
We form a common denominator for the top fractions, then simplify:
$\displaystyle \frac{\frac{1}{(x+h)^{2}}-\frac{1}{x^{2}}}{h}=\frac{x^{2}-(x+h)^{2}}{hx^{2}(x+h)^{2}}=\frac{x^{2}-(x^{2}+2xh+h^{2})}{hx^{2}(x+h)^{2}}=-\frac{2x+h}{x^{2}(x+h)^{2}}$