Functions can't have multiple y values have the same x value.
[(-5, 1), (-3, 2), (-1, 3) (1, 4), (3, 5)] ** No repeating x-values.
[(-2, 1), (-4, 2), (0,3), (4, 1), (-2,5)]
[(-1, 5), (-1,4), (-1, 3), (-1, 2) (-1, 1)]
[(-6, -4), (-4, -2), (0, 0), (-4, 2) (-6, 4)]
Answer:
[(-5, 1), (-3, 2), (-1, 3) (1, 4), (3, 5)]
