#### Answer

(a) increasing at: $(-\infty, -2) \cup (2, +\infty)$
(b) decreasing at: $(-2, 2)$
(c) none

#### Work Step by Step

(a) The graph is rising from the left up to $x=-2$ as well as from $x=2$ to the right. Thus, the function is increasing in the interval $(-\infty, -2) \cup (2, +\infty)$.
(b) The graph is falling from $x=-2$ to $x=2$. Thus, the function is decreasing in the interval $(-2, 2)$.
(c) The graph has no interval where its value is constant.