Part A: 6m + 12 + 42m, which combines to form 48m + 12. Another expression is 12 + 48m, because using the commutative property of addition, it is equivalent.
Part B: As I stated earlier, using the commutative property of addition, your expression 12 + 48m is equivalent to 48m + 12.
Part C: If you substitute 2 for m, you will get 108. If they are talking about the main equation, then if you substitute 2 for m, you will have 6(2 + 2 + 14) = 108.
