Answer:

Explanation:

This is the Arithmetic Sequence Formula->

1) The d represents your difference of the equation. You can find it by finding a pattern between the three numbers given, which is -5
2) Now that we've found our difference, we can plug it into this lovely sequence we have
(by the way, your n represents your term that you plug into the equation)
3)
This also means that
is our first term, which is 2
4) Simplify
-->

5)

The formula is confusing at first, but it becomes easier once your learn the patterns!