I really really need help ASAP

In a graph with several intervals o data how does a constant interval appear? what type of scenario produces a constant interval?

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 is the simplified form of (3.25x10^3)(7.8x10^6) written in scientific notation?