# How do you write a rule for the nth term 7,5,3,1,-1?

##### 2 Answers

each term is going down by 2

this gives -2, -4, -6, -8

to get the sequence we need to find the adjuster

opposite of -2 is +2, 7+2=9

#### Explanation:

First of all, notice that this is an arithmetic sequence, i.e. two consecutive terms differ by a common difference. In this case, two consecutive terms always differ by

We start from

The general rule is what we just described with words: start from the initial value

So, the rule is

You can confirm this by building some terms using the definition: given the starting value

as you can see, the index of the term is equal to the times we have to subtract