Question

The first term of an arithmetic sequence is -5, and the tenth term is 13. Find the common difference.

2

1.8

8/9

Answer 1

d = 2.

Explanation:

First term = -5

10th term = -5 + 9d where d is the common difference, so

-5 + 9d = 13

9d = 18

d = 2.

Answer 2

2

Explanation:

If the common difference is d we can write:

-5 + 9d = 13

9d = 18

d = 2