Answer
$125x^{3}$
Work Step by Step
According to the definition of negative exponents, $a^{-n}=\frac{1}{a^{n}}$ (where $a\ne0$).
Therefore, $(\frac{1}{5x})^{-3}=\frac{1}{(\frac{1}{5x})^{3}}=(\frac{5x}{1})^{3}=\frac{5^{3}x^{3}}{1^{3}}=\frac{125x^{3}}{1}=125x^{3}$.
