$\dfrac{a}{a^2+2} +\dfrac{b}{b^2+2}+\dfrac{c}{c^2+2} \leq 1$
2) Giải hệ PT:
$ x^3-3x=y$
$ y^3-3y=z$
$ z^3-3z=x$
Edited by maimaimottinhyeu, 28-09-2010 - 11:37.
Edited by maimaimottinhyeu, 28-09-2010 - 11:37.
Edited by jin195, 28-09-2010 - 15:20.
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