Omar mows lawns for $9.25 an hour. He spends $7.50 on gas for the mower. How much does he make if he

Omar mows lawns for $9.25 an hour. He spends $7.50 on gas for the mower. How much does he make if he works h hours?

His revenue R(h) where h is the number of hours is denoted by:
R(h) = Hourly Rate * h - Gas cost
R(h) = 9.25h - 7.50