gmat math bible simple bt weird answer!

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by Ian Stewart » Thu Mar 19, 2009 4:46 am
If x is equal to the absolute value of something, then x cannot be negative. Notice that as long as x and y aren't both zero, -x^2 - y^2 will always be negative, so cannot be equal to x.
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by vkb16 » Tue Mar 24, 2009 6:47 am
asper mgmat material and gmat bible, say x= |a-b|,
we follow two steps
if x is negative, x<0,
then x= -(a-b) =>x=b-a

again, if x>0,

then x=a-b

shudnt we follow this in this situation as well?