Question

Which graph is an example of a function?
A) A
B) B
C) C
D) D

Answer 1

The definiton of a function is that "for every x-value/input there is exactly one y-value/output."

When working with graphs, you can judge if this is true by using the vertical line test:

If you can draw any vertical line that hits the graph more than once, then the graph is NOT the graph of a function.

Which graph passes the vertical line test?

Answer 2

your answer should be d