Use the rational zeros theorem to write a list of all potential rational zeros of the function f(x)=3x^2 +39x^2+39x +27

Charlie is at an amusement park that has 18 different rides. each ride costs $1.75. the function c(r) = 1.75r represents the total amount of money that charlie will spend if he goes on r rides, but he never goes on the same one more than once. what domain and range are reasonable for the function?