5. Is the sequence 47,4721,8221,397,… arithmetic? If so, find the common difference.
6. Is the sequence 2,4,8,16,… arithmetic? If so, find the common difference.
7. An arithmetic sequence has the first term a1=18 and common difference d=−8. What are the first five terms?
8. An arithmetic sequence has terms a3=11.7 and a8=−14.6. What is the first term?
9. Write a recursive formula for the arithmetic sequence −20,−10,0,10,…
10. Write a recursive formula for the arithmetic sequence 0,−12,−1,−32,…, and then find the 31st term.
11. Write an explicit formula for the arithmetic sequence 78,2924,3724,158,…
12. How many terms are in the finite arithmetic sequence 12,20,28,…,172?