Question

Tell whether the sequence is arithmetic. If it is, what is the common difference? -19,-11,-3,5,...

Answer 1

Every next number is incremented by 8 from the previous number hence the sequence is arithmetic and the common difference is 8.

Hope this helps.

Answer 2

The given sequence is arithmetic and common difference is 8.

Explanation:

Given that :

- 19, - 11, - 3, 5......

Here, a = - 19 ; a is the first term of the series.

Now, For common difference-

d =
`t_(2) - t_(1)` =
`t_(3) - t_(2)` =
`t_(4) - t_(3)`

Let
`t_(1) = - 19,  t_(2) = - 11`

d = - 11 - (-19)

= -11 + 19

= 8

Let
`t_(3) = - 3,  t_(2) = - 11`

d = - 3 -(-11)

= - 3 + 11

= 8

Let
`t_(4) = 5,  t_(3) = - 3`

d = 5 - (-3)

= 8

In each condition common difference d is same therefore the given sequence is arithmetic and common difference d = 8.