Grayson is a kickboxing instructor who will be teaching classes at a local gym. To get certified as an instructor, he spent a total of $130. Grayson will be earning a base salary of $58 per month from the gym, plus an additional $12 for every class he teaches. If Grayson teaches a certain number of classes during his first month as an instructor, he will earn back the amount he spent on certification. How much will Grayson's expenses and earnings be? How many classes will that take?
