Answer
$2xy^3\sqrt[5]{2xy^2}$
Work Step by Step
Write $64$ as $2^6$ to obtain:
$=\sqrt[5]{2^6x^6y^{17}}$
RECALL:
$\sqrt[n]{a^n}=a$
Factor the radicand (expression inside the radical sign) so that at least one factor is a perfect fifth power, and then use the rule above to simplify and obtain:
$=\sqrt[5]{(2^5x^5y^{15}) \cdot 2xy^2}
\\=\sqrt[5]{2^5x^5(y^3)^5 \cdot 2xy^2}
\\=2xy^3\sqrt[5]{2xy^2}$
