4 Write the correct answer in the box. Substitute numerical values into the expression for all known variables.

Jeff wants to purchase a television for his first apartment. The television costs $750. He can get a zero-interest loan for the television if he pays $100 per month. At the same time, he puts away $200 per month in savings. To figure out when his savings will equal the remaining amount he owes on the television, he starts writing a system of equations:

Equation 1: y = 200x
Equation 2:

Write the second equation in the system.