ANSWER:
-1 or 2
Given the following set of inputs and ouputs:
x y
-1 -2
? 0
2 2
The possible values for x that would make this shown not to be a function is -1 or 2
Foe a relation to be a function, no value of x should be related to two or more values of y.
Example:
Not a function:
(x, y) ==> (-1, -2), (-1, 0), (2, 2)
Here, -1 is related to two values of y, therefore this relation is not a function.