A binary operation * is defined on the set of positive integers is such x*y = 2x-3y+2 for all positive integers x and y. The binary operation is?
- commutative and close on the set of positive integers
-
neither commutative nor closed on the set of positive integers
- commutative but not closed on the set of positive integers
- not cummutative but closed on the set of positive integers
The correct answer is: B
Explanation
X * Y = 2X - 3Y + 2
2*3 = 2(2) - 3(3) + 2
=4-9+2
= -3
But -3 does not belong to positive integer
There is an explanation video available .