This ain’t a question but I need a best friend

Whats the name of the vertical axis

The total cost of anja’s trip to the dentist was $628.35. she paid a flat fee of $89.95 which included the checkup and cleaning and then had 4 cavities filled, each of which cost the same amount. which shows the correct equation and value of x, the cost of each cavity filling?

What are the values of each variable in the diagram below?