How to know that number is irrational list all things . plz

Which shows the correct solution of the equation 1/2a+2/3b=50, when b=30?

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 circles have their centers on the x-axis? check all that apply.