Question

Which of the following relations is a function?

Answer 1

{ (-2, 4), (-1, 3), (5, 2), (1, 4) }



{ (1, 7), (1, 8), (2, 7), (3, 8) }



{ (2, 4), (4, 6), (4, 8), (6, 4) }



{ (5, 7), (6, 3), (8, 6), (5, 4) }

Answer 2

A

Answer 3

{ (-2, 4), (-1, 3), (5, 2), (1, 4) }

Answer 4

the first element must not be repeat
{ (5, 7), (6, 3), (8, 6), (5, 4) }
is not because
(5,7) ,(5,4) 5 seem twice
do like that