Answer: 2 solutions.
The given equation breaks down into these two equations
3x+12 = 18 and 3x+12 = -18
Basically 3x+12 equal to plus 18 and minus 18. This is due to the fact that something like |x| = 7 means x = 7 or x = -7, ie those x values are exactly seven units away from zero on the number line.
If you want to solve each equation, then
3x+12 = 18
3x = 18-12
3x = 6
x = 6/3
x = 2 is one solution
and
3x+12 = -18
3x = -18-12
3x = -30
x = -30/3
x = -10 is the other solution
