Which of the following is not a function
{(-1,-2), (0, -3),(1,-2), (2,1)}
{(-1,-2), (0, -3), (1, -2), (2, 1)
{(-2, 2), (-1,1),(0,0),(1,1)}
{(-2,0), (2,2), (2, -2), (7,3)}
There are two x-values that are the same, making it not a function. Notice, this is not the same in the other sets, because each x corresponds to exactly one y-value in the other functions.
