Question

Which of the following relations is NOT a function?
A. {(1, 1), (2, 4), (3, 6), (4, 8)}
B. {(−5, 25), (5, 25), (−6, 36), (6, 36)}
C. {(4, −4), (3, −3), (3, 3), (4, 4)}
D. {(3, 12), (5, 20), (7, 28), (8, 32)}

Answer 1

Which choice has a repeated x value?

Answer 2

C

Answer 3

????

Answer 4

Which of the following tables does not represent a function?
A.
x y
−8 9
−4 9
0 9
4 9
B.
x y
3 5
1 3
−2 0
−9 −7
C.
x y
4 −1
1 −4
4 1
1 4
D.
x y
−10 12
−4 6
2 0
8 6

Answer 5

Same idea. Wherever you see a repeated x value, that means that x maps to more than one y value. That makes it NOT a function.

Answer 6

For it to be a function, x must map to exactly one y value.