Find g(f(x)) f(x)=3x g(x)=3x

$f (x) = 3 x$ $g (x) = 3 x$

Set up the composite result function.

$g (f (x))$

Evaluate $g (3 x)$ by substituting in the value of $f$ into $g$ .

$g (3 x) = 3 (3 x)$

Multiply $3$ by $3$ .

$g (3 x) = 9 x$