144 x m - 309.6 = 50.4
Add 309.6 to both sides:
144 - 309.6 + 309.6 = 50.4 + 309.6
Simplify the arithmetic:
144 x m = 50.4 + 309.6
144 x m =360
m = 5/2
3.4m questions
4.3m answers