Question

{(1,2), (2,1), (3,2), (4,3), (5,2)} is a function or not ???​

Answer 1

Exactly one means one but two or more: {(1,2);(2,3);(3,4);(2,5)} includes the points (2,3) and (2,5) . Therefore this set of pairse is not a function.

Answer 2

dont know

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