Could someone give me a run down of how these problems are done? i used a calculator to get the answers but now i want to know how to do these on my own

Look at the following graph of the given equation. determine whether the equation is a function. explain why or why not.

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?

Abe is a triangle. can you use the sss postulate or the sas postulate to prove triangle abc = triangle aed? by sss only neither apply both apply by sas only