Question

Determine if the given sequence is an arithmetic sequence. If it is, find the common difference, d. -9, -2, 5, 12, …

Answer 1

Given:

-9, -2, 5, 12, …

The difference between -9 and -2 is

`-2-(-9)=-2+9=7`

The difference between -2 and 5 is

`5-(-2)=5+2=7`

The difference between 5 and 12 is

`12-5=7`

The difference between each term is the same value 7.

Hence we get the common difference d =7.

The given sequence is an arithmetic sequence since it has a common difference.