Algebra 1: Common Core (15th Edition)

$d=28$
The quantity inside of the parenthesis is being multiplied by 1/4. Thus, we first multiply both sides by 4/1 (the reciprocal of 1/4) to find that $16=d-12$. We now need to get the d alone. Thus, we cancel out the subtraction by adding 12 on both sides. Thus, we obtain that $d=28$.