Sort out the cards as functions or non-function PLEASE HELP

Giuseppi's pizza had orders for $931.00 of pizzas. the prices were $21 for a large pizza, 514 for a medium pizza, and $7 for a small pizza. the number of large pizzas was two less than four times the number of medium pizzas. thenumber of small pizzas was three more than three times the number of medium pizzas. how many of each size of pizza were ordered?

What is the distance between the points (2 -3) and (-6 4) on the coordinate plane

Prove that 16^4-2^13-4^5 is divisible by 11.