A rectangular bird feeder costs $18.00. A cylindrical bird feeder costs $24.00. The expected cost to keep the rectangular bird feeder filled is $3.00 per week. The expected cost the keep the cylindrical bird feeder filled is $2.00 per week. The equation below models the break-even point. 18 + 3x = 24 + 2x

What does x represent?

-the total cost to fill the rectangular bird feeder after any number of weeks
-the total cost to fill the cylindrical bird feeder after any number of weeks
-the number of weeks the bird feeders are filled
-the number of bird feeders purchased each week