Question

Does each relation represent a function

(1,3), (2,5), (2,7), (4,9)
(1,3), (2,5), (3,7), (4,9)
(1,3), (1,5), (1,7), (1,9)
(1,3), (2,3), (3.3), (4.3)

Answer 1

the first one yes

the 2nd one yes

the 3rd one no 4th also no

Explanation: