## Precalculus (6th Edition)

$\color{blue}{\text{not a real number}}$
RECALL: $\sqrt[n]{a} = a^{1/n}$ Use the rule above by to obtain: $\sqrt[4]{-256} = (-256)^{1/4}$ Since there is no real number $a$ such that $a^{4} = -256$, then the given expression is: $\color{blue}{\text{not a real number}}$