Given 3(x+7)=-12, we could do 2 things: we could distribute or divide both sides by 3. It appears that we will divide both sides by 3.
3(x+7)/3=-12/3 Divide 3 on both sides to isolate X by Division P.O.E.
x+7=-4.
Then, x+7-7=-4-7 by Subtraction P.O.E. to isolate X.
X=-11 is your answer