What are two equations that model the data? What are the domain and range of each equation?

Question

Month|Sales
2 | 3
4 | 5
6 | 4
8 | 6
10 | 5
12 | 12
14 | 16
16 | 22
18 | 26
20 | 32

I am very confused about how to do this question.

Answer 1

I don't see any obvious relationship, nor does Wolfram

http://www.wolframalpha.com/input/?i=plot+%7B%282%2C3%29%284%2C5%29%286%2C4%29%288%2C6%29%2810%2C5%29%2812%2C12%29%2814%2C16%29%2816%2C22%29%2818%2C26%29%2820%2C32%29%7D