Answer
$\dfrac{1}{x^{2}}$
Work Step by Step
When we raise a power to a power, we simply multiply the two powers together:
\begin{align*}
(x^{\frac{2}{3}})^{-3}&= x^{\frac{2}{3}({-3})}\\
&=x^{-\frac{6}{3}}\\
&=x^{-2}
\end{align*}
Simplified expressions should not have negative exponents.
To get rid of the negative exponent, use the rule $a^{-m} = \frac{1}{a^m}$ to obtain:
$$x^{-2}=\frac{1}{x^{2}}$$
