Answer:
i thick it is c so good luck
Step-by-step explanation:
Hope this helps, even though I do feel that it could be wrong. Welp, I gave it my best shot.
3x + 12 = 3
(multiply 3 by the variables in the parentheses)
3x + 12 = 3
add 12 to each side
3x = 15
divide each side by 3
X=5