What is 3/8 as a proportional ratio fraction

Write the equation for the parabola that has x− intercepts (−2,0) and (4,0) and y− intercept (0,4).

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?

How do you write something in scientific notation?