Givens
The cost of one piece of new equipment = 400
The number of new items needed = 4
Cost of one month's use = 35 dollars.
Income from 1 month's use = y
Number of members = x
Problem
Robert, the owner of a gym on the coast of Louisiana, has to replace 4 machines after a hurricane came through. Each machine costs 400. The gym cannot operate without these 4 machines. The gym will be be down for 1 month. He has x members who each pay 35 dollars for the use of the gym for a month. What is the total amount (y), that he is "out" for the month.
y = 35x + 400*4.