Answer
16
Work Step by Step
We know that $a^{\frac{m}{n}}=(\sqrt[n] a)^{m}$ (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, $(-8)^{\frac{4}{3}}=(\sqrt[3] -8)^{4}=(-2)^{4}=16$
We know that $\sqrt[3] -8=-2$ because $(-2)^{3}=-8$
