9. Which of these relations are functions? Select all that apply. (4,4), (5, 6), (6, 8), (6, 10), (7, 12) (6, 9), (7., 19), (8, 29), (8, 39), (9, 49) (4, 4), (5, 4), (6, 4), (7, 4), (8, 4) (7,33), (8, 30), (9, 27), (10, 24), (11, 21) (1, 2), (2, 2), (2,-2), (3,-2), (4, -2)
