Question

find a formula for the nth term of the arithmetic sequence. first term 9 common difference -2 $a_n = ?n + $

Explanation:

Step1: Recall arithmetic sequence formula

The general formula for the nth term of an arithmetic sequence is $a_n = a_1 + (n-1)d$, where $a_1$ is the first term and $d$ is the common difference.

Step2: Substitute given values

Substitute $a_1=9$ and $d=-2$ into the formula:
$a_n = 9 + (n-1)(-2)$

Step3: Expand and simplify the formula

$a_n = 9 - 2n + 2 = -2n + 11$

Answer:

$a_n = -2n + 11$