33x + 173 = total
To find this you have the equation 33x + m = 338. It tells us that this is after 5 months, so now we put 5 into x and multiply to get 165. Now the equation looks like 165 + m = 338. Subtract 165 from both sides to find m, which leaves us with 173 for the initial fee. Now you just have to rewrite the equation to be 33x + 173 = Total amount