Look at these sets of ordered pairs.
W) {(8, 9), (2, 3), (0, -2), (10,-9)}
X) {(0, 0), (5, 10), (-3, 3}}
Y){(1, 1), (2, 2), (3, 3), (4,4)}
z) {(-10, 1), (-9, 3), (-4,5)}
Which of the sets represent functions?