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.

First one...(a#b)#a=b
it's just changed around
see.........a#(b#a)=b a# is at the front
............(a#b)#a=b a# is at the back

(b#a) b is before a
(a#b) a is before b

there is no difference!!

a#(b#a)=b = (a#b)#a=b

Posted by Ashlee on 2003-10-21 05:32:09