A little help pls gracias (thank you)

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?

Which of the following contains a variable?

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.