Please help me out with this

Use set buikder notation to represent the following set: {, -2, -1, 0}

How do you solve a question like this?

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?