Identification of function with a relation of graph (vertical line test): If a vertical line intersects the graph more than once, then the graph is not a function and otherwise the relation a function.
\Observe the relation in the graph, the relation is not a function. Because its graph does not pass the vertical line test. If draw a vertical line in the graph then it intersect graph more than once (two times).
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No, the relation is not a function.