Answer
(a) $(-\infty,-1)\cup(-1,1)\cup(1,\infty)$
(b) $\emptyset$
Work Step by Step
(a) Use the given graph, the solution to $f(x)\lt0$ can be found as $(-\infty,-1)\cup(-1,1)\cup(1,\infty)$
(b) Use the given graph, the solution to $f(x)\gt0$ is an empty set $\emptyset$