Final answer:
To simplify the expression 9m - 7m + 2m, combine like terms. The simplified expression is 4m.
Step-by-step explanation:
To simplify the expression 9m - 7m + 2m, we combine like terms. Like terms have the same variable raised to the same power. In this case, the like terms are 9m, -7m, and 2m. Adding them together, we get 4m. So, the simplified expression is 4m.