Ответ:

\[\left(-\frac45a^{-5}b^{-12}\right)^{-3}\cdot(5a^9b^{17})^{-2}\]

\[=\left(-\frac45\right)^{-3}a^{15}b^{36}\cdot5^{-2}a^{-18}b^{-34}\]

\[=-\frac{125}{64}\cdot\frac1{25}a^{-3}b^2=-\frac5{64}\cdot\frac{b^2}{a^3}.\]

Ответ: \(-\frac{5b^2}{64a^3}\).