What do you do when your stuck on a math problem ?

Using the quadratic formula find the zeros of the given polynomial -5x^2+3x-11

In the polynomial below, what number should replace the question mark to produce a difference of squares? x2 + ? x - 36

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?