X is more than 1 or x greater than 4

To decrease an amount by 16% what single multiplier would you use

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?

Use long division to indentify (12xto the second power+15x-8)divided by 3x