Answer
$h=6$
Work Step by Step
We need to get the h alone. Thus, we cancel out the addition by subtracting 20 on both sides. This leaves us with the equation $-3h=-18$. In order to cancel out multiplication, we use division, so we divide both sides by -3 to get that $h=6$. We plug 6 in for h and confirm that our answer is, indeed, correct.