Answer:
Subtraction, and division.
Step-by-step explanation:
First you need to subtract to isolate the variable x.
3x + 2(-2) = 12(-2)
Matt is now left with 3x = 10, he now needs to use division.
3x/10 = 3.3x
I hope this is correct, I am rusty with this topic. Good luck with your studies.