SOLUTION: How do you know if a relation is a function?

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Question 232754: How do you know if a relation is a function?
Answer by dpaulin(12) About Me  (Show Source):
You can put this solution on YOUR website!
The vertical line test:
draw a vertical line through the graph if it intersects the graph more than once it is not a function
This is a function
graph+%28300%2C300%2C-10%2C10%2C-10%2C10%2Cx%5E2%29
say you have a graph like x=y%5E2 which would have that U shape, but rotated 90 degrees, that would not be a function. hence my lacking ability to graph it.