Answer
$\dfrac{32}{x^{5}}$
Work Step by Step
Using $\left( \dfrac{a}{b} \right)^{x}=\dfrac{a^x}{b^x}
$, the given expression, $
\left( \dfrac{x}{2} \right)^{-5}
$, is equivalent to
\begin{array}{l}
\dfrac{x^{-5}}{2^{-5}}
.\end{array}
Using $a^{-x}=\dfrac{1}{a^{x}}$ and $\dfrac{1}{a^{-x}}=a^x$, the expression above is equivalent to
\begin{array}{l}
\dfrac{2^{5}}{x^{5}}
\\\\=
\dfrac{32}{x^{5}}
.\end{array}