The product of six and a number is multiplied by nine

Given f(x)= 9x+1 and g(x)=x^3, choose the expression (f*g)(x)

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?

Solve -.016x= -16. need solving this