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 September 4th, 2014, 03:18 PM #1 Member   Joined: Jun 2014 From: Alberta Posts: 56 Thanks: 2 Basic Algebraic Proof Is there anything wrong with this algebraic proof? Please give a rigorous critique. Proof that a/b/(c/d) = ad/(bc) if b, c, d don't equal 0: a/b/(c/d) = a/b(c/d)^(-1) [existence of multiplicative inverses] = a/b(cd^(-1))^(-1) = a/bc^(-1)(d^(-1))^(-1) [Does the operation made in this step comply with a prior question that had us prove (ab)^(-1) = a^(-1)b^(-1)?] = a/b(1/c)1/(d^(-1))d/d = a/b(1/c)d = a/bd/c = ad/(bc) The reason why I posted this is because the book's answer has pretty much the same thing except that it brings b up as b^(-1) and then brings it back down at the end. I feel like I am missing something here.

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