Answer
$x^{6}y^3z^{15}$
Work Step by Step
Using the laws of exponents, the given expression, $
\left( \dfrac{x^2y}{z^{-5}} \right)^{3}
$, is equivalent to
\begin{array}{l}\require{cancel}
\dfrac{x^{2(3)}y^3}{z^{-5(3)}}
\\\\=
\dfrac{x^{6}y^3}{z^{-15}}
\\\\=
x^{6}y^3z^{15}
.\end{array}