Question

Which relation is a function?

{(2, 3), (1, 5), (2, 7)}
{(-1, 5), (-2, 6), (-3, 7)}
{(11, 9), (11, 5), (9, 3)}
{(3, 8), (0, 8), (3, -2)}

Answer 1

The second one

Explanation:

In a function an input has a distinct output, so if I put 3 into a function and got 8, that is my answer and nothing else, if I put 3 again and get -2 then it isn't a function because I got a different answer. In the 1st, 3rd and 4th one there are two outputs for the same input so they aren't functions.

Answer 2

The second option because one same input cannot have two different outputs
For example, x + 2 = y
If I put in 3, y has to equal 5, nothing else.
This makes the second option the only option that is a function
Hope this helps!