An auditorium has rows of seats that increase in length the farther the row is from the stage. The first row has 28 seats, the second row has 31 seats, the third row has 34 seats, the fourth row has 37 seats, and so on. A) Let an be the number of seats in the nth row. Write an explicit formula of the form an = b + c to model this situation An B) Find ag C) If the last row has 73 seats, how many rows are there?