Ans: $\dfrac{n^{35}}{m^6}$
$\begin{array}{cl}
& \dfrac{m^9}{(m^3n^{-7})^5} \\
= & \dfrac{m^9}{m^{15}n^{-35}} \\
= & \dfrac{n^{35}}{m^6}
\end{array}$
$\begin{array}{cl}
& \dfrac{m^9}{(m^3n^{-7})^5} \\
= & \dfrac{m^9}{m^{15}n^{-35}} \\
= & \dfrac{n^{35}}{m^6}
\end{array}$
