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Determine whether or not the definition of * given below gives a binary operation. In the event that * is not a binary operation give justification of this.(iii) On R, define * by a*b = ab2 (iv) On Z+ define * by a * b = |a − b|

(iii) Since, on R, define by a*b = ab2

Let

   

Thus, * is a binary operation on R.

(iv) Given on Z+ define * by a * b = |a − b|

Let

   

Therefore,

a * b ∈ Z+, ∀ a, b ∈ Z+

Thus, * is a binary operation on Z+.