Chapter 5 - Graphs and the Derivative - 5.2 Relative Extrema - 5.2 Exercises - Page 272: 39

$x=5$ is the only point of extrema (relative minimum).

Observe the graph. The coordinate point $(5,-8)$ denotes minimum for the function in the window $[-10\times10]$ and $[-15,30]$. This implies that $x=-5$ is the point of relative minima. There is no relative maximum for this function as observed. Also, since $(5,-8)$ is a sharp point, $f'(5)=0$.