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.