Answer
$x^{\frac{2}{3}}$
Work Step by Step
We are told on page 419 that $\sqrt[n] (a^{m})=a^{\frac{m}{n}}$ (where m and n are positive integers greater than 1 with $\frac{m}{n}$ in simplest form and $\sqrt[n] a$ is a real number).
Therefore, $\sqrt[3] (x^{2})=x^{\frac{2}{3}}$