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Cancelling squares 
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#1
May1505, 12:14 AM

P: 8

Greetings friends,
I have come across an argument on cancelling the squares on either side of an equation. For example if the equation is (ab)^2=(cb)^2 my argument is that i can cancel the squares by taking the square root of both sides as to get (ab)=(cb) and hence a=c. But others says that squares cannot be remove as such. So I thought i would consult you guys. What do you think, am i wrong or are they wrong? thanx for your help! 


#2
May1505, 12:36 AM

P: 1,059

A^2=B^2 then that tells us that A^2B^2 = 0, or that (AB)(A+B) = 0, and so we have that either A=B, or A=B.
This is rather evident since, consider that (2)^2=2^2. 


#3
May1505, 12:15 PM

Math
Emeritus
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Thanks
PF Gold
P: 39,682

In other words, if (ab)^2= (cd)^2 then EITHER ab= cd OR ab= dc.



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