Question

Question content area top
Part 1
Which of these relations are​ functions?
Question content area bottom
Part 1
Select all that apply.
A.
​(4,4), (5,4),​ (6,4), (7,4),​ (8,4)
B.
​(6,9), (7,19),​ (8,29), (8,39),​ (9,49)
C.
​(7,33), (8,30),​ (9,27), (10,24),​ (11,21)
D.
​(4,4), (5,6),​ (6,8), (6,10),​ (7,12)

Answer 1

A and C.

Reason: In A and C each input (first coordinate) appears only once. In B input 8 appears twice with different outputs (29 and 39), and in D input 6 appears twice with different outputs (8 and 10), so B and D are not functions.