Question

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

1.8
2
8/9

Answer 1

d = 2

Explanation:

The n th term of an arithmetic sequence is

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Here a₁ = - 5 and a₁₀ = 13, thus

a₁ + 9d = 13, that is

- 5 + 9d = 13 ( add 5 to both sides )

9d = 18 ( divide both sides by 9 )

d = 2