giải hệ a;$\left\{\begin{matrix}x_{1}^{2}+ax_{1}+(\frac{a-1}{2})^2=x_{2}
\\ x_{2}^{2}+ax_{2}+(\frac{a-1}{2})^2=x_{3}\\ ... \\x_{2003}^{2}+ax_{2003}+(\frac{a-1}{2})^2=x_{1} \end{matrix}\right.$
b;$\left\{\begin{matrix} \frac{xy}{x+y}=1-z\\ \frac{yz}{y+z}=2-x\\ \frac{xz}{x+z}=2-y \end{matrix}\right.$
Edited by killerdark68, 21-09-2014 - 14:57.