giải các hệ phương trình sau:
1) $\left\{\begin{matrix} 2x^{2} -15xy+4y^{2}-12x+45y-24=0& & \\ x^{2}-2y^{2}-3x+3y+xy=0 & & \end{matrix}\right.$
2)$\left\{\begin{matrix} x^{2}(y+1)(x-y+1)=3x^{2}-4x+1 & \\ xy+x+1=x^{2} & \end{matrix}\right.$
3)$\left\{\begin{matrix} x(x+1)(2x+5y)=144& \\ x^{2}+4x+5y=24& \end{matrix}\right.$
4)$\left\{\begin{matrix} x\sqrt{y}+y\sqrt{x}=30& \\ x\sqrt{x}+y\sqrt{y}=35& \end{matrix}\right.$
5)$\left\{\begin{matrix} y^{2}=x^{3}-4x^{2}+7x& \\ x^{2}=y^{3}-4y^{2}+7y& \end{matrix}\right.$
6)$\left\{\begin{matrix} 3x^{2}y-y^{2}-2=0& \\ 3y^{2}x-x^{2}-2=0& \end{matrix}\right.$
7)$\left\{\begin{matrix} 2x^{2}-y^{2}=1& \\ xy+x^{2}=2& \end{matrix}\right.$
8)$\left\{\begin{matrix} x^{2}-4xy-2y^{2}=3& \\ 2x^{2}-xy+3y^{2}=4& \end{matrix}\right.$
9)$\left\{\begin{matrix} x-\sqrt{y}=1 & \\ y-\sqrt{z}=1 & \\ z-\sqrt{x}=1 & \end{matrix}\right.$
10)$\left\{\begin{matrix} x-\frac{1}{y}=1 & \\ y-\frac{1}{z}=1 & \\ z-\frac{1}{x}=1 & \end{matrix}\right.$
11)$\left\{\begin{matrix} x^{2}+2xy-3y^{2}=0& \\ x\left | x \right |+y\left | y \right |=-2& \end{matrix}\right.$
12)$\left\{\begin{matrix} x^{2}+xy+y^{2}=84& \\ x+\sqrt{xy}+y=14& \end{matrix}\right.$
13)$\left\{\begin{matrix} \sqrt{\frac{x+1}{2x-1}}+\sqrt{\frac{2y-1}{x+1}}=2,5& \\ x-y=2& \end{matrix}\right.$$\left\{\begin{matrix} \sqrt{\frac{x+1}{2x-1}}+\sqrt{\frac{2y-1}{x+1}}=2,5& \\ x-y=2& \end{matrix}\right.$