Answers

  • Brainly User
2016-06-24T12:59:16+08:00
By drawing a vertical line.  This is called the vertical line test.

If the vertical line intersects one point in only in a graph, then it's function.

If the vertical line intersects more than one point in a graph, then it's not a function.

What does it mean?

If the vertical line intersects more that one point, it means there are two values of x (range - the first elements) that correspond to one value of y (domain-the second elements).  Remember that a function does not repeat the same element/ values in domain (x).
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