$1+\frac{2}{3}\sqrt{x-x^{2}}=\sqrt{x}+\sqrt{1-x}$
$\frac{2}{\sqrt{x+1}+\sqrt{3-x}}=1+\sqrt{3+2x-x^{2}}$
$\left\{\begin{matrix} x^{2}-y^{2}+x=1 & \\2xy+y=3 & \end{matrix}\right.$
$\left\{\begin{matrix} x^{2}+y^{2}-xy-3x+3y=0 & \\ xy+2x=6 & \end{matrix}\right.$
$\sqrt{5x^{2}-14x+9}-\sqrt{x^{2}-x-20}=5(x+1)$
Edited by anhhuy980413, 11-08-2015 - 21:16.