The expression -3m - [2m + (5 - m)] + 7 was simplified as 2 - 4m. Without simplifying, explain how you can show that it has been simplified correctly.

Answer:

To show that the expression has been simplified correctly without performing the simplification steps, you can substitute a value for the variable m into both the original expression and the simplified expression. If the expressions are equivalent, they will yield the same numerical result. For example, if you let m = 1, both expressions should evaluate to the same value.