So, to solve these kind of questions, we have to break down the problem. First we have to calculate $h(3)$
$h(3)= 4(3) +5 => 17$
Now we have to plug in the result into g(x) because you could say that $h(3)$ lies inside $g(x)$.
So, $g(17) = 2(17) +3 => 37$