1. $\left\{\begin{matrix} x^3+2y^2-4y+3=0 & \\x^2 +x^2y^2-2y=0 & \end{matrix}\right.$
2. $\left\{\begin{matrix} x+y+\sqrt{x^2-y^2}=12 & \\y\sqrt{x^2-y^2}=12 & \end{matrix}\right.$
3. $\left\{\begin{matrix} xy+x+y=x^2-2y^2 & \\x\sqrt{2y}-y\sqrt{x-1}=2x-2y & \end{matrix}\right.$
4. $\left\{\begin{matrix} x^4+2x^3y+x^2y^2=2x+9 & \\x^2+2xy=6x+6 & \end{matrix}\right.$
5. $\left\{\begin{matrix} x(x+y+1)-3=0 & \\(x+y)^2-\frac{5}{x^2} +1=0 & \end{matrix}\right.$
6. $\left\{\begin{matrix} \sqrt{2x^2y^2-x^4y^4}=y^6+x^2(1-x) & \\\sqrt{1+(x+y)^2}+x(2y^3+x^2)\leq 0 & \end{matrix}\right.$
7. $\left\{\begin{matrix} xy+x+1=7y & \\x^2y^2+xy+1=13y^2 & \end{matrix}\right.$
8. $\left\{\begin{matrix} y^6+y^3+2x^2=\sqrt{xy-x^2y^2} & \\4xy^3+y^3+\frac{1}{2}\geq 2x^2+\sqrt{1+(2x-y)^2} & \end{matrix}\right.$
9. $\left\{\begin{matrix} \frac{2x^2}{1+x^2}=y & \\ \frac{2y^2}{1+y^2}=z & \\ \frac{2z^2}{1+z^2}=x & \end{matrix}\right.$
10.$\left\{\begin{matrix} \frac{1}{x}+\frac{1}{y}+\frac{1}{z}=2 & \\ \frac{2}{xy}-\frac{1}{z^2} =4& \end{matrix}\right.$
11. $\left\{\begin{matrix} \frac{x^4}{y^2}+\frac{y^4}{z^2}+\frac{z^4}{x^2}=12 & \\ x^2+y^2+z^2=12& \end{matrix}\right.$
12. $\left\{\begin{matrix} x+y+z=1 & \\ \frac{x}{y}+\frac{y}{z}+\frac{z}{x}=\frac{x+y}{y+z}\frac{y+z}{x+y}+1& \end{matrix}\right.$
13. $\left\{\begin{matrix} x^2+y^2+z^2=1 & \\ yz+zx+2xy=-1& \end{matrix}\right.$
14. $\left\{\begin{matrix} x+y+z+\frac{1}{x}+\frac{1}{y}+\frac{1}{z}=\frac{51}{4} & \\ x^2+y^2+z^2+\frac{1}{x^2}+\frac{1}{y^2}+\frac{1}{z^2}=\frac{771}{16}& \end{matrix}\right.$
15. $\left\{\begin{matrix} \frac{x^2}{y+z}+\frac{y^2}{z+x}+\frac{z^2}{x+y}=3 & \\ \sqrt{xy}+\sqrt{yz}+\sqrt{zx}=6& \end{matrix}\right.$
Bài viết đã được chỉnh sửa nội dung bởi ptk1995: 12-04-2012 - 21:51