how to change negative exponents

Here is a number of other examples.

http://web2.0calc.com/questions/indices-especially-negative-indices

How to change negative exponents

$$\boxed{\ \left( \dfrac{a}{b} \right)^{-n} =\left( \dfrac{b}{a} \right)^{n} \ }$$

Example:

$$a=2 \quad b=1\quad n=3\\\\ \left( \dfrac{2}{1} \right)^{-3} =2^{-3} =\left( \dfrac{1}{2} \right)^{3} =\dfrac{1}{2^3}$$