Question

How do you write an equation for the nth term of the arithmetic sequence: -3, -5, -7, -9, ...?

Answer 1

`a_n=-2n-1`

Explanation:

The formula for an arithmetic sequence is `a_n=a_1 +(n-1)d`
where `a_1` is the first term and `d` is the difference between terms.

In this case `a_1=-3` and `d=-2`

`a_n=-3+(n-1)(-2)=-3-2n+2 =-2n-1`

`a_n=-2n-1`