## Intermediate Algebra for College Students (7th Edition)

RECALL: When the index, $n$ is even, the value of $a$ in $\sqrt[n]{a}$ cannot be negative since its nth root will not be a real number. The given radical has an even index (6). Since the number inside the radical is negative, its 6th root will not be a real number. Thus, the given expression is not a real number.