Ans: $\dfrac{a^{17}}{b^{14}}$
$\begin{array}{cl}
& \dfrac{(a^3b^{-2})^4}{a^{-5}b^6} \\
= & \dfrac{a^{3 \times 4}b^{-2\times 4}}{a^{-5}b^6} \\
= & \dfrac{a^{12}b^{-8}}{a^{-5}b^6} \\
= & \dfrac{a^{12-(-5)}}{b^{6-(-8)}} \\
= & \dfrac{a^{17}}{b^{14}}
\end{array}$
