Answer
a) $(-\infty,-3)\cup(1,\infty)$
b) $[-3,1]$
Work Step by Step
a) The equation:
$g(x)=f(x)$
has the solutions $x=-3$ and $x=1$.
The solution of the inequality
$f(x)\lt g(x)$
contains all the values of $x$ for which the graph of $f$ is below the graph of $g$:
$(-\infty,-3)\cup(1,\infty)$
b) The solution of the inequality
$f(x)\geq g(x)$
contains all the values of $x$ for which the graph of $f$ is above the graph of $g$ including the intersections:
$[-3,1]$