### Home > CCA2 > Chapter 11 > Lesson 11.3.1 > Problem11-93

11-93.

Each of the following sums is the beginning of an arithmetic series. Find the $n$th term of each series, for the specified value of $n$.

1. $(-2) + (-5) + (-8) +$ ..., $n = 12$

How is this sequence progressing?
How can you use that to determine what the $12$th term will be?

$-35$

2. $9 + 15 + 21 +$ ..., $n = 20$

Use the same method as part (a).