What set of ordered pairs represents y as a function of x?

The set {(1, 2), (2, -3), (3, 4), (4, -5)} represents y as a function of x
Question 2:
The best statement describes the relation is "The relation represents y as a function of x, because each value of x is associated with a single value of y" ⇒ 3rd answer
Question 4:
There are missing options so we can not find the correct answer
Question 5:
The sets {(1 , 1), (2 , 2), (2 , 3)} and {(1, 2), (1, 3), (1, 1)} do not represent y as a function of x ⇒ 1st and 4th answers
Step-by-step explanation:
The relation is a function if each value of x has ONLY one value of y
Ex: The set {(3 , 5) , (-2 , 1) , (4 , 3)} represents y as a function of x because x = 3 has only y = 5, x = -2 has only y = 1, x = 4 has only y = 3
The set {(4 , 5) , (-2 , 1) , (4 , 3)} does not represent y as a function of x because x = 4 has two values of y 5 and 3