One concert ticket is $5 and the other is $9. There are 500 seats. My expenses are estimated at $4000. Determine equations for income, profit, and expenses if all 500 seats are filled.

Are my equations-
expenses:y=400
income:4x+2500
profit:y=4x-1500

If there are x seats at $5, then

income = 5x + 9(500-x)
expenses = 4000
profit = income - expenses