First, combine like terms.
4m+5m = 9m
9m + 9 - 12 = 42
9-12= -3
9m - 3 = 42
Second, apply the inverse operation to isolate the variable.
9m - 3 = 42
+3 +3
9m = 45
Third, divide 9 by both sides to solve for m.
\(\frac{9m}{9} = \frac{45}{9}\)
m = 45/9
m = 5
Answer: \(m = 5\)
