10-05-2015 - 07:53
Cho các số thực x,y,z thỏa mãn $2^{-x}+2^{-y}+2^{-z}=1$
12-04-2015 - 10:04
$\left\{\begin{matrix}7^{2x+\sqrt{x+1}}-7^{2+\sqrt{x+1}}+2015x\leq 2015 & & \\ x^{2}-(m+2)x+2m+3\geq 0 & & \end{matrix}\right.$
22-01-2015 - 00:31
1. $x^{2}+y^{2}=xy+x+y$
$x^{2}-y^{2}=3$
2. $\sqrt{x^{2}+2x+6}=y+1$
$x^{2}+xy+y^{2}=7$
3. $x\sqrt{x}-y\sqrt{y}=8\sqrt{x}+2\sqrt{y}$
$x-3y=6$
4. $\sqrt{2}(x-y)=\sqrt{xy}$
$x^{2}-y^{2}=3$
16-10-2014 - 21:58
$2(2x+1)^{3}+2x+1=(2y-3)\sqrt{y-2})$
$\sqrt{4x+2}+\sqrt{2y+4}=6$
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