Simplify and solve this equation: 4m + 9 + 5m - 12 = 42.

A. m = - 4

B. m = 4

C. m = - 5

D. m = 5

4m + 9 + 5m - 12 = 42

Given the equation combine all similar terms found on a side of the equation.

You can add the "m" and get: 9m + 9 - 12 = 42

You can combine the 9 and the - 12 and get: 9m - 3 = 42

To get the "m" alone add or subtract any number necessary from the left side so the number is 0, and do the same to the right: 9m - 3 + 3 = 42 + 3, leaving you: 9m = 45

Divide each side by the number of "m" you have: (9m) / 9 = 45/9 which simplifies to m=5.

I think that the answer is D. m = 5