## Algebra 2 (1st Edition)

Consider a negative number $s$. $s^4$ is positive but $s^5$ is negative. Also, consider a number $r$ which is positive. Both $r^4$ and $r^5$ are positive. Thus the sign of $a$ is important as a fourth root will have multiple roots or no roots, and the fifth root will have 1 either way, whether it be positive or negative.