Which relation is a function? {(−2, 1), (−2, 2), (−2,  7), (−2, 8)} {(−2, 2), (−7, 7), (−1,  1), (−8, 8)} {(1, −7), (2, −8), (−2,  7), (1, 8)} {(−2, 1), (−7, −1), (2,  8), (−7, −8)}

Aschool puts on a play. the play costs $1,200 in expenses. the students charge $4.00 for tickets. there will be one performance of the play in an auditorium that seats 500 people. what is the domain of the function that shows the profit as a function of the number of tickets sold?