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Identification of function: A function is a relation in which each element of the domain is paired with exactly one element of the range.
\Observe the relation as the graph, the relation is not a function. Observe the coordinate pairs in the graph, each element in the domain is paired with one element the range. Or the graph passes through the vertical line test. If draw a vertical line in the graph then it intersect the graph at only one point.
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Yes, the relation is a function.