Which sets of ordered pairs represent relations that are functions? you may choose more than one correct answer,
((1), (2.0), (3, 0), (4,0))
(2,3), (2, 4), (2,5), (2,6)}
((11), (2, 2), (3, 3), (4,4))
{(1,3), (-1,4), (1,4), (-1,3)
(6,6), (-6, 6), (5-5), (-5,5))