Question

Which relation represents a function?

A. (0, 0), (2, 3), (2, 5), (6, 6)
B. (3, 5), (8, 4), (10, 11), (10, 6)
C. (negative 2, 2), (0, 2), (7, 2), (11, 2)
D.(13, 2), (13, 3), (13, 4), (13, 5)

Answer 1

Answer: Choice C

For choices A, B and D, the x values repeat in some way.

Choice A has x = 2 repeated

Choice B has x = 10 repeated

Choice D has x = 13 repeated

A function cannot have repeated x values. Put another way, a function is only possible if any given x input goes to exactly one y output.

Choice C shows each x value listed once only. If you were to graph these points, then the relation will pass the vertical line test.