Answer
$a=-8$
Work Step by Step
We need to get the a alone. Thus, we cancel out the addition by subtracting 54 on both sides. This leaves us with the equation 2a=-16. In order to cancel out multiplication, we use division, so we divide both sides of the equation by 2 to get that $a=-8$. We plug -8 in for a and confirm that our answer is, indeed, correct.