Question

Which relation represents a function?

StartSet (0, 0), (2, 3), (2, 5), (6, 6) EndSet
StartSet (3, 5), (8, 4), (10, 11), (10, 6) EndSet
StartSet (negative 2, 2), (0, 2), (7, 2), (11, 2) EndSet
StartSet (13, 2), (13, 3), (13, 4), (13, 5) EndSet



A
B
C
D

Answer 1

Answer: Choice C

{ (-2,2), (0,2), (7,2), (11,2) }

Here we don't have any repeated x values.

In choice A, x = 2 repeats. In other words, x = 2 leads to multiple y outputs. So this is not a function. Choices B and D are similar stories. A function is only possible if every x leads to exactly one y value only. The graph must pass the vertical line test.

Side note: the y values can repeat, but the function won't be one-to-one.