Final answer:
The vertical line test is used to determine if a graph is a function. If no vertical line intersects the graph at more than one point, then the graph is a function.
Step-by-step explanation:
The vertical line test is used to determine if a graph is a function. According to the test, if no vertical line intersects the graph at more than one point, then the graph is a function.
For example, let's consider the graph of a linear function, such as y = 2x + 3. If we draw a vertical line anywhere on the graph, it will intersect the graph at exactly one point, satisfying the test.
However, if we have a graph where a vertical line intersects at more than one point, such as a parabola, it fails the vertical line test and is not a function.
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