Answer
$3a\sqrt[4]{2a}$
Work Step by Step
Using the properties of radicals, the expression $
3\sqrt[4]{32a^5}-a\sqrt[4]{162a}
$ simplifies to
\begin{array}{l}
3\sqrt[4]{16a^4\cdot2a}-a\sqrt[4]{81\cdot2a}
\\=
3\cdot2a\sqrt[4]{2a}-a\cdot3\sqrt[4]{2a}
\\=
6a\sqrt[4]{2a}-3a\sqrt[4]{2a}
\\=
3a\sqrt[4]{2a}
.\end{array}