$$\\(6j^{-2})^{-3}\\
=6^{-3}\;\;j^{-2*-3}\\\\
=\frac{6^{-3}\;\;j^{6}}{1}\\\\
=\frac{j^{6}}{6^3}\\\\
=\frac{j^{6}}{216}\\\\
$Now if j is an ordinary pronumeral then the question is finished$\\
$but if j is the imaginary number $ \sqrt{-1} \qquad then\\\\
(\sqrt{-1})^6=((\sqrt{-1})^2)^3=(-1)^3=-1\\\\
$ so the final answer would be $
\frac{-1}{216}$$
$$\\(6j^{-2})^{-3}\\
=6^{-3}\;\;j^{-2*-3}\\\\
=\frac{6^{-3}\;\;j^{6}}{1}\\\\
=\frac{j^{6}}{6^3}\\\\
=\frac{j^{6}}{216}\\\\
$Now if j is an ordinary pronumeral then the question is finished$\\
$but if j is the imaginary number $ \sqrt{-1} \qquad then\\\\
(\sqrt{-1})^6=((\sqrt{-1})^2)^3=(-1)^3=-1\\\\
$ so the final answer would be $
\frac{-1}{216}$$