Answer:
Im either gonna say, the last one or the first. Please dont hate me.
Answer: 
Step-by-step explanation:
If you meant to solve for "z", then refer to the attachment below.
Solve for x. Isolate the x. Note the equal sign. What you do to one side, you do to the other. Do the opposite of PEMDAS.
First, multiply 3 to both sides
6(3) = ((x + 2)/3)(3)
18 = x + 2
Finally, isolate the x. Subtract 2 from both sides
18 (-2) = x + 2 (-2)
x = 18 - 2
x = 16
16 is your answer for x
hope this helps
X=9
3x-12=x+6
2x-12=6
2x=18
X=9