Question

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)}

Answer 1

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

Answer 2

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

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.