Can someone please help me with 3 and 4?

Me find the value of x each figure.

Shared decision making is always a positive strategy to take

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?