(i)Since, On Z+, defined * by a * b = a – b
If a = 1 and b = 2 in Z+, then
For a = 1 and b = 2,
a * b ∉ Z+
Thus, * is not a binary operation on Z+.
(ii) Given Z+, define * by a*b = a b
Let
Thus, * is a binary operation on R.
(i)Since, On Z+, defined * by a * b = a – b
If a = 1 and b = 2 in Z+, then
For a = 1 and b = 2,
a * b ∉ Z+
Thus, * is not a binary operation on Z+.
(ii) Given Z+, define * by a*b = a b
Let
Thus, * is a binary operation on R.