Question

Which relation is a function?

Responses

{(5, 0), (0, 1), (5, 2), (4,4)}

{(1, 2), (2,4), (−1, 2), (0,3)}

{(0, 1), (−4, 1), (4, 2), (−4,−1)}

{(3, 2), (2,1), (−1, 2), (3,3)}

Answer 1

I think not. When x = 2, y = both 2 and then 3

{(1, 2), (2,4), (−1, 2), (0,3)}
works better

Answer 2

The relation {(3, 2), (2,1), (−1, 2), (3,3)} is a function.