Question

Write an equation for the nth term of the arithmetic sequence −15, −33, −51, −69, .... An equation for the nth term of the

Answer 1

Given:

The arithmetic sequence is −15, −33, −51, −69.

To find:

The nth term of the arithmetic sequence.

Solution:

We have,

−15, −33, −51, −69

Here,

First term: a = -15

Common difference is

`d = -33-(-15)`

`d = -33+15`

`d = -18`

Now, nth term of an arithmetic sequence is

`a_n=a+(n-1)d`

Substitute a=-15 and d=-18.

`a_n=-15+(n-1)(-18)`

`a_n=-15-18n+18`

`a_n=-18n+3`

Therefore, the nth term of the given arithmetic sequence is
`a_n=-18n+3`.