Zachary is a kickboxing instructor who will be teaching classes at a local gym. To get certified as an instructor, he spent a total of $109. Zachary will be earning a base salary of $64 per month from the gym, plus an additional $15 for every class he teaches. If Zachary teaches a certain number of classes during his first month as an instructor, he will earn back the amount he spent on certification. How many classes will that take? How much will Zachary's expenses and earnings be?

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