Answer
$\dfrac{1}{\sqrt[3]{y^4}}$ or $\dfrac{1}{\left(\sqrt[3]{y}\right)^4}$
Work Step by Step
Recall the basic property of negative exponents (pg. 383):
$a^{-m}=\frac{1}{a^m}$
Applying this property, we get:
$\dfrac{1}{y^{\frac{4}{3}}}$
Next, recall the rational exponent property (pg. 382):
$a^{\frac{m}{n}}=\sqrt[n]{a^m}=(\sqrt[n]{a})^m$
Applying this property the given expression (with $m=4$, $n=3$, $a=y$), we get:
$=\dfrac{1}{\sqrt[3]{y^4}}$ or $\dfrac{1}{\left(\sqrt[3]{y}\right)^4}$
