Please help pre alg find x

Acomputer store bought a program at a cost of $10 and sold it for $13. find the percent markup

5. (03.02)if g(x) = x2 + 3, find g(4). (2 points)1619811

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?