Answer
$\dfrac{c^{15}}{125a^9b^6}$
Work Step by Step
$\bigg(\dfrac{5a^3}{b^{-2}c^5}\bigg)^{-3}$
$\dfrac{5^{-3}a^{3\times (-3)}}{b^{-2\times (-3)}c^{5\times (-3)}}$
$\dfrac{5^{-3}a^{-9}}{b^6c^{-15}}$
$\dfrac{c^{15}}{5^3a^9b^6}$
$\dfrac{c^{15}}{125a^9b^6}$