The cost of the visit to the dentist can be expressed as the cost equals 100x+50.
The initial cost of the appointment would be $50; no matter how many cavities one has, they would still have to pay $50.
The cost of each cavity is represented as 100x, because each cavity costs $100. x represents the number of cavities, as we do not know how many cavities there are.
50 is the amount of money it is for a visit and the x represents how many cavities are being filled and the 100 is for how much it is per cavity to be filled. For example if you needed 3 cavities filled then it would be 50+(100x3).
(Btw sorry if the equation for the step-by-step explanation is incorrect)
