Answer
(a)
Increasing on $(-4, -2.5)\cup(-1,1)\cup(3, 4)$,
Decreasing on $(-2.5, -1)\cup(1, 3).$
(b)
No absolute maximum.
No absolute minimum.
Local maximum at $(-2.5,1), (1,2)$ and $(4, 2)$
Local minimum at $(-1,0)$ and $(3, 1)$.
Work Step by Step
See image below.