Plss help it’s a test due in 10 minutes and I don’t get it

Given the graph below state whether or not the relation is a function, and give the domain and range.

Find x to the nearest hundredth place

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?