# The third term of an arithmetic sequence is 14, and the ninth term is -1. How do you find the first four terms of the sequence?

##### 1 Answer

#### Explanation:

You can write an equation (or formula) for each term in an AP.

"The third term is 14" can be written with the formula as:

"The ninth term is -1 " can be written as:

Now there are two equations with two unknowns.

Solve them simultaneously (as a system).

A-B:

This sequence is given by

For

Each term is 2.5 less than the previous term: