Answer
$Volume = \frac{27}{x^{6}z^{3}}$
Work Step by Step
The formula for the volume of a cube is= $s^{3}$, where s is the length of a side
We know that one side, $s=\frac{3x^{-2}}{z}$
So to find volume we must cube said value, to get $(\frac{3x^{-2}}{z})^{3}=\frac{27x^{-6}}{z^{3}}=\frac{27}{x^{6}z^{3}}$
