Nine less than twice x is three more than x what is the value of x

How do you determine whether a relationship represented as as graph is linear or nonlinear

We just started the introduction into circles and i have no idea how to do this.

Amanda went into the grocery business starting with five stores. after one year, she opened two more stores. after two years, she opened two more stores than the previous year. if amanda expands her grocery business following the same pattern, which of the following graphs represents the number of stores she will own over time?