Write a system of equations to describe the situation below, solve using substitution, and fill in the blanks.

Luke wrote a business plan for an entrepreneurship class, and now he has to make bound copies. Luke could use a printer who charges a setup fee of $51 and $6 for every copy printed. Another possibility is to go to the office supply store, where he could pay an up-front fee of $24 and $7 per copy. There is a certain number of copies that makes the two options equivalent in terms of cost. How much would the copies cost? How many copies is that?