# Example:3 The 1st term of an arithmetic sequence is 200 and the common nunmber is -10 What is the formula an? What is the 20th term?

##### 1 Answer

#### Explanation:

An arithmetic sequence starts with an initial value and adds the same constant with every iteration. The terms are thus written like this:

In your case, the starting number

This means that the formula for the generic term is

To find the