Question

Which of the following is not a function?

A{ (0,1), (1,2), (2,3), (3,4)}
B.{(0,2), (1,3), (4,3), (1,2)}
C.{(1,3), (4,2), (2,0), (3,4)}
D.{(1,2), (2,2), (3,2), (4,2)}

Answer 1

B. {(0,2), (1,3), (4,3), (1,2)}

Explanation:

A relation is not a function if the same input value maps to multiple output values. Essentially, if any x is repeated, it is not a function.

The second set, {(0,2), (1,3), (4,3), (1,2)}, has x-values of 0, 1, 4, 1, so 1 is repeated. It is not a function.