**PLEASE HELP!! 60 POINTS** Seats in a theater are curved from the front row to the back. The front row has 10 chairs, the second has 16 and the third has 22, and so on.

a. Write a recursive rule for this series:

b. Write an explicit rule for this series:
If you simplify, please show all steps.

c. Using the explicit formula, find the number of chairs in row 5 (show work):

d. The auditorium can hold 17 rows of chairs. Write a sigma notation for this series, and then use either series formula to calculate how many chairs can fit in the auditorium.