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Z is set of integers, <Z, ∗> forms group if ∗ is: 
Question



Z is set of integers, <Z, ∗> forms group if ∗ is: 

A.

∗(a, b) = a  + b + 2

B.

∗(a, b) = 2a + b

C.

∗(a, b) = (a + b)/2

D.

∗(a, b) = a2 + b

Correct option is A



Since it fails the associativity test, it cannot form a group.

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