Answer:
{(2,-1), (4, -2), (6, -3), (8, -4)}
Step-by-step explanation:
The other ordered pairs have a common domain value which means they are not a function.
For example:
{(5,7), (5,8), (10,3)} would not be a function because the 5 is repeating
However
{(2,6), (4,6), (22,7)} would be function because there are no numbers in the x part of the ordered pair that repeat. (x,y)
I hope you can see the pattern now
