Ans: $\dfrac{x^9}{y^5}$
$\begin{array}{cl}
& \dfrac{xy^7}{(x^{-2}y^3)^4} \\
= & \dfrac{xy^7}{x^{-2 \times 4}y^{3 \times 4}} \\
= & \dfrac{xy^7}{x^{-8}y^{12}} \\
= & \dfrac{x^{1-(-8)}}{y^{12-7}} \\
= & \dfrac{x^9}{y^5}
\end{array}$
$\begin{array}{cl}
& \dfrac{xy^7}{(x^{-2}y^3)^4} \\
= & \dfrac{xy^7}{x^{-2 \times 4}y^{3 \times 4}} \\
= & \dfrac{xy^7}{x^{-8}y^{12}} \\
= & \dfrac{x^{1-(-8)}}{y^{12-7}} \\
= & \dfrac{x^9}{y^5}
\end{array}$
