Answer
$\frac{-1}{x(x+h)}$
Work Step by Step
Step 1. Perform operations to the numerator:
$\frac{1}{x+h}-\frac{1}{x}=\frac{x-x-h}{x(x+h)}=\frac{-h}{x(x+h)}$
Step 2. Use the above results in the original expression, we have:
$\frac{\frac{1}{x+h}-\frac{1}{x}}{h}=\frac{\frac{-h}{x(x+h)}}{h}=\frac{-1}{x(x+h)}$
