Which relation is not a function?
a
b
{(1,3), (2,4), (3,5), (4,6)
(6,3). (4,7).(-6,3), (4,-1)}
{(8,9), (7,9), (3,9),(4,9)}
{(5,2), (3,7), (-2,4),(0,7)}
С
HELP PLAS