The numbers of seats in the first 12 rows of a high-school

Last updated: 7/19/2022

The numbers of seats in the first 12 rows of a high-school auditorium form an arithmetic sequence. The first row has 9 seats. The second row has 11 seats. a. Write a recursive formula to represent the sequence. b. Write an explicit formula to represent the sequence. c. How many seats are in the 12th row?