Use traces to sketch and identify the surface 9x^2-y^2+z^2=0

The triangles are similar. what is the value of x? x=

How do you solve a question like 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?