How many degrees of freedom does the variance within groups have for an ANOVA on 5 groups with 10 samples in each group

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?

Ten times the square of a non-zero number is eqaul to ninety times the number

How to find the exponential function y=ca^x, with points (1,2) and (2,1)