Consider a binary operation # that is closed under the set of integers (if a and b are integers, then a#b is an integer).
Assume that, for all integers a and b, it is true that (a#b)#a=b.
Prove that a#(b#a)=b.
(In reply to
re: A simple solution by SilverKnight)
You say "Commutative means that (a#b)#c = a#(b#c)." That is the associative property. The commutative property is that a#b = b#a.

Posted by Charlie
on 20031019 13:25:13 