In the equation 3x 2 + 6x = 12, the value of c is:

12
-12
6

1. 4(n+3)=16, n+3=4, n=1
2. m/4+3=24, m/4=21, m=84
1. three added to a number n implies n+3, 4 times that sum is 4 (n+3), to solve divide both sides by 4 then subtract three from both sides.
2. a number divided by 4 means n/4 adding it to three n/4+3, to solve subtract 3 from both sides then multiply both sides by 4