\textbf{146-} Is the relation $ad = bc \Leftrightarrow (a,b)\,R\,(c,d)$ an equivalence relation on $\mathbb{R}^2$? If it is an equivalence relation, which point does the graph $[(2,6)]$ pass through?
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(1) It is not an equivalence relation. \hfill $(1,2)$ (2) \hfill $(1,3)$ (3) \hfill $(2,3)$ (4)
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