Answer
$\dfrac{y^3}{8x^3}$
Work Step by Step
Using the laws of exponents, the given expression, $
\left( \dfrac{2x}{y} \right)^{-3}
,$ simplifies to
\begin{array}{l}\require{cancel}
\left( \dfrac{y}{2x} \right)^{3}
\\\\=
\dfrac{y^3}{2^3x^3}
\\\\=
\dfrac{y^3}{8x^3}
.\end{array}
