Question

Which relation is a function?

•{(4, 2), (3, 3), (2, 4), (3, 2)}
•{(1, 4), (2, 3), (3, 2), (4, 1)}
•{(1, -1), (-2, 2), (-1, 2), (1, - 2)}
• {(1, 2), (2, 3), (3, 2), (2, 1)}​

Answer 1

•{(1, 4), (2, 3), (3, 2), (4, 1)}

Explanation:

this is correct because the values are not repeted

Answer 2

•{(1, 4), (2, 3), (3, 2), (4, 1)}

Explanation:

The second answer is the function because all the other choices show the x values repeated and the second answer has all x values unique.

I'm not very good at explaining but that's the answer.