Question

The amount of money in your savings account after m months is represented b A = 135m + 225 . After how many months do you have $765 in your savings account.

Answer 1

the answer is four months

Answer 2

You just have to rearrange the formula.
So:
765 = 135 x m + 225
765 - 225 = 135 x m
540 = 135 x m
m = 540 / 135
m = 4

So four months.