Question

How do you write the nth term rule for the arithmetic sequence with d=-12 and `a_1=80`?

Answer 1

`n^(th)` term is `92-12n`

Explanation:

If in a arithmetic sequence, `a_1` is first term and common difference is `d`, the `n^(th)` term is given by `a_n=a+(n-1)d`

As `a_1=80` and `d=-12`, `n^(th)` term is

`a_n=80+(n-1)xx(-12)`

= `80-12n+12`

= `92-12n`