Answer: x = -3
Explanation:
Distribute 3 through the parenthesis
12x + 3 -4x + 3 = -18
Collect Like Terms
8x + 3 + 3 = -18
8x+6+-18
Move constant to the right-hand side and change its sign
8x = -18 - 6
Calculate the difference
8x = -24
Divide both sides
x = -3