Answer
$\dfrac{27}{8a^{6}}$
Work Step by Step
Using the laws of exponents, the given expression, $
\left( \dfrac{2a^2}{3} \right)^{-3}
$, is equivalent to
\begin{array}{l}\require{cancel}
\dfrac{2^{-3}a^{2(-3)}}{3^{-3}}
\\\\=
\dfrac{3^{3}a^{-6}}{2^{3}}
\\\\=
\dfrac{27}{8a^{6}}
.\end{array}
