Answer
$-6y^2\sqrt[5] {2x^3y}$.
Work Step by Step
The given expression is
$=-3y\sqrt[5] {64x^3y^6}$
Identify the power of $5$ factors.
$=-3y\sqrt[5] {2^52^1x^3y^5y^1}$
Factor into two radicals.
$=-3y\sqrt[5] {2^5y^5}\sqrt[5] {2^1x^3y^1}$
Simplify.
$=-3y2y\sqrt[5] {2x^3y}$
$=-6y^2\sqrt[5] {2x^3y}$.
