What is the domain of the relation r: {(3, −2), (1, 2), (−1, −4), (−1, 2)}? is it a function? {−1, 1, 3}; no {−1, −1, 1, 3}; yes {−4, −2, 2 2}; no {−4, −2, 2}; yes?

The list of first values of the ordered pairs is {3, 1, -1, -1}. When put into order, they are {-1, 1, 3}. Since one is repeated, the relation is NOT a function.

The appropriate choice is the first one:

... {-1, 1, 3}; no