Answer
$2y^{\frac{3}{4}}$
Work Step by Step
$\sqrt[4]{16y^{3}}\qquad$...write in exponential form, $\sqrt[n]{a^{m}}=a^{\frac{m}{n}}$
$=(16y^{3})^{\frac{1}{4}}\qquad$...use power of a product.
$=16^{\frac{1}{4}}(y^{3})^{\frac{1}{4}}\qquad$...simplify.
$=(2^{4})^{\frac{1}{4}}y^{\frac{3}{4}}$
$=2y^{\frac{3}{4}}$
