$$\sqrt[4]{\frac{81a^{12}6^{-20}}{16x^{8}y^{-16}}}$$
$\frac{\left(|a|\right)^{3}y^{4}}{5184x^{2}}$
$-\frac{\left(\frac{|a|}{x}\right)^{3}y^{4}}{2592}$
