2012 . | x - 2011| + (x-2011)2 = 2013 . | 2011 - x|
|x-2011|.|x-2011| + 2012 . | x - 2011| - 2013 . | 2011- x| =0
|x - 2011|.| x - 2011| + 2012 .| x - 2011| - 2013 | x - 2011| = 0
| x- 2011| .| x -2011| - | x - 2011| = 0
| x - 2011|. { | x - 2011| - 1} = 0
\(\left[{}\begin{matrix}\left|x-2011\right|=0\\\left|x-2011\right|-1=0\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=2011\\x=2012\\x=2010\end{matrix}\right.\)
Kết luận x \(\in\) { 2010; 2011; 2012}