SOLUTION: Let x = 2012(a - b), y = 2012(b - c), and z = 2012(c - a), where a,b,c are real numbers, and assume xy + yz + zx is not = 0. Compute (x^2 + y^2 + z^2)/(xy + yz + zx).

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Question 1078282: Let x = 2012(a - b), y = 2012(b - c), and z = 2012(c - a), where a,b,c are real numbers, and assume
xy + yz + zx is not = 0. Compute (x^2 + y^2 + z^2)/(xy + yz + zx).

Found 2 solutions by Edwin McCravy, ikleyn:
Answer by Edwin McCravy(20064)   (Show Source): You can put this solution on YOUR website!
Let x = 2012(a - b), y = 2012(b - c), and z = 2012(c - a), where a,b,c are real numbers, and assume
xy + yz + zx is not = 0. Compute (x^2 + y^2 + z^2)/(xy + yz + zx).
The 2012 was just put in there to complicate matters.  It could
have been any number whatever.  Most likely this problem was made
up 5 years ago in in 2012.  Let's just divide everything through 
by 2012: 

, , and 

Add all those equations together:





Multiply thru by 2012:



So 

We want to compute:



Substitute -x-y for z













Edwin

Answer by ikleyn(52879)   (Show Source): You can put this solution on YOUR website!
.
Let x = 2012(a - b), y = 2012(b - c), and z = 2012(c - a), where a,b,c are real numbers, and assume
xy + yz + zx is not = 0. Compute (x^2 + y^2 + z^2)/(xy + yz + zx).
~~~~~~~~~~~~~~~~~~~~~

It could be done shorter.

x = 2012(a - b), y = 2012(b - c), and z = 2012(c - a)  ===>

x + y + z = 2012*(a-b+b-c+c-a) = 0.


Hence 

0 =  =  =  +   ===>

 =   ===>

 = -2.

Solved.



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