# How do you combine x/(x+2) - x/(x-2)?

Use $\left(x + 2\right) \left(x - 2\right)$ as common denominator and so:
$\frac{x}{x + 2} - \frac{x}{x - 2} = \frac{x \left(x - 2\right) - x \left(x + 2\right)}{\left(x + 2\right) \left(x - 2\right)} =$
$= \frac{\cancel{{x}^{2}} - 2 x \cancel{- {x}^{2}} - 2 x}{\left(x + 2\right) \left(x - 2\right)} = \frac{- 4 x}{\left(x + 2\right) \left(x - 2\right)}$