#### Answer

$m=-5$

#### Work Step by Step

We need to get the m alone. Thus, we cancel out the addition by subtracting 8 on both sides. This leaves us with the equation $3m=-15$. In order to cancel out multiplication, we use division, so we divide both sides of the equation by 3 to get that $m=-5$. We plug -5 in for m and confirm that our answer is, indeed, correct.