Which set of ordered pairs represents a function?

{ (0,1), (2, - 1), (-7,6), (0,3) }

{ (-5,6), (9,4), (-7, 2), (-9,6) }

{ (6, - 6), (-7,8), (9,3), (9, - 5) }

{ (-2,1), (-1,-9), (-2,-6), (2, - 2) }

There is a rule for functions:

One input (x-value) can only have one output (y-value).

If one input has more than one output, it is not a function.

(This doesn't apply to outputs, one output can have more than one input and still be a function)

(0,1), (2, - 1), (-7,6), (0,3) }

This isn't a function because the input 0 has more than one output of 1 and 3

{ (-5,6), (9,4), (-7, 2), (-9,6) }

This is a function because each input has only one output.

{ (6, - 6), (-7,8), (9,3), (9, - 5) }

This is not a function because the input 9 has more than one output of 3 and - 5

{ (-2,1), (-1,-9), (-2,-6), (2, - 2) }

This is not a function because the input - 2 has more than one output of 1 and - 6

the second set, { (-5,6), (9,4), (-7, 2), (-9,6) }

Step-by-step explanation:

a function is when the domain has only one range, in all the sets there are multiple domains (x) with diff ranges (y), but not in the second one.