Answer
$x^{8}y^{20}$
Work Step by Step
Using $a^{m/n}=\sqrt[n]{a^m}=(\sqrt[n]{a})^m$, the given expression, $
\left( \sqrt[3]{x^2y^5} \right)^{12}
,$ is equivalent to
\begin{array}{l}\require{cancel}
(x^2y^5)^{12/3}
\\\\=
(x^2y^5)^{4}
\\\\=
x^{2(4)}y^{5(4)}
\\\\=
x^{8}y^{20}
.\end{array}