Why is this a function?!

Alice is paying her bill at a restaurant. but tax on the cost of a male is 5%. she decides to leave a tip 20% of the cost of the meal plus the tax

Three students, javier, sam, and corrine, participated in a fundraiser where people donated a certain amount of money per lap that the student ran. each student also had some initial donations that were collected before the run. the equations that represent each student's total donation, y, based on the number of laps ran, x, is shown below. match each equation with the correct rate of change for that student.

Millie decided to purchase a $17,000 msrp vehicle at a 4% interest rate for 6 years. the dealership offered her a $2700 cash-back incentive, which she accepted. if she takes all these factors into consideration, what monthly payment amount can she expect? a.$223.73b.$243.25c.$274.61d.$235.51