The simplified expression is 74 - 90m.
To solve this problem
The terms enclosed in parenthesis must all have the -10 divided among them before being combined with like phrases.
4 - 10(9m - 7) = 4 - 90m + 70
Now, combine the constant terms:
4 - 90m + 70 = (4 + 70) - 90m
74 - 90m
Therefore, the simplified expression is 74 - 90m.