Tham khảo nha:
Lấy pt (1) từ đi pt (2) vế theo vế ta được:
\(\frac{y}{x}-\frac{x}{y}=2,1\)
\(\Leftrightarrow y^2-x^2=2,1xy\)
\(\Leftrightarrow x^2+2,1xy-y^2=0\)
\(\Leftrightarrow\frac{1}{10}\left(5x-2y\right)\left(2x+5y\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\frac{2y}{5}\\x=-\frac{5y}{2}\end{matrix}\right.\)
Thay vào pt đầu là được 
Giải hpt : a) \(\left\{{}\begin{matrix}xy^2+2x+y=4xy\\\frac{1}{xy}+\frac{1}{y^2}+\frac{y}{x}=3\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}x^2+y^2+\frac{4y}{x}=22\\\frac{3}{x^2+y^2-1}+\frac{2x}{y}=1\end{matrix}\right.\)
Giải hpt : a) \(\left\{{}\begin{matrix}\left(x^2+y^2\right)\left(x+y+1\right)=25\left(y+1\right)\\x^2+xy+2y^2+x-8y=9\end{matrix}\right.\) b) \(\left\{{}\begin{matrix}x^2+y^2+6xy-\frac{1}{\left(x-y\right)^2}+\frac{9}{8}=0\\2y-\frac{1}{x-y}+\frac{5}{4}=0\end{matrix}\right.\)
c) \(\left\{{}\begin{matrix}\frac{x}{x^2-y}+\frac{5y}{x+y^2}=4\\5x+y+\frac{x^2-5y^2}{xy}=5\end{matrix}\right.\) d) \(\left\{{}\begin{matrix}3xy+y+1=21x\\9x^2y^2+3xy+1=117x^2\end{matrix}\right.\)
e) \(\left\{{}\begin{matrix}x\left(x^2-y^2\right)+x^2=1\sqrt{\left(x-y^2\right)^3}\\76x^2-20y^2+2=\sqrt[3]{4x\left(8x+1\right)}\end{matrix}\right.\)
giải HPT sau :
\(\left\{{}\begin{matrix}\frac{1}{x+1}+\frac{1}{y+1}=1\\xy+x+y=3\end{matrix}\right.\)
Giải PT và HPT:
1)\(\left\{{}\begin{matrix}xy+x+y=3\\\frac{1}{x^2+2x}+\frac{1}{y^2+2y}=\frac{2}{3}\end{matrix}\right.\)
2)\(\left(\sqrt{x+4}-2\right)\left(\sqrt{4-x}+2\right)=2x\)
3)\(\left\{{}\begin{matrix}xy\left(x+y\right)=2\\9xy\left(3x-y\right)+6=26x^3-2y^3\end{matrix}\right.\)
4)\(\left\{{}\begin{matrix}x^2-2xy+x-2y+3=0\\y^2-x^2+2xy+2x-2=0\end{matrix}\right.\)
Giải HPT:
\(\left\{{}\begin{matrix}\frac{1}{\sqrt{x^2+1}}+\frac{1}{\sqrt{y^2+1}}=\frac{2}{\sqrt{xy+1}}\\x+\frac{y\sqrt{3}}{\sqrt{xy-3}}=2\sqrt{6}\end{matrix}\right.\)
Giải hệ phương trình
a)\(\left\{{}\begin{matrix}2x^3=y+1\\2y^3=x+1\end{matrix}\right.\)
b)\(\left\{{}\begin{matrix}x^2+\frac{1}{y^2}+\frac{x}{y}=7\\x^2-\frac{1}{y^2}=3\end{matrix}\right.\)
c)\(\left\{{}\begin{matrix}x^2+y^2=10\\x+y=4\end{matrix}\right.\)
d)\(\left\{{}\begin{matrix}xy+x+y=19\\x^2y+xy^2=84\end{matrix}\right.\)
e)\(\left\{{}\begin{matrix}x^2+xy+y^2=4\\x+xy+y=2\end{matrix}\right.\)
giải hpt: \(\left\{{}\begin{matrix}xy+x+y=0\\xy^2-4=x^2\end{matrix}\right.\)
giải hpt:
1,\(\left\{{}\begin{matrix}x^2y^2-2x+y^2=0\\2x^2-4x+3+y^3=0\end{matrix}\right.\)
2. \(\left\{{}\begin{matrix}\left(x^2-xy\right)\left(xy-y^2\right)=25\\\sqrt{x^2-xy}+\sqrt{xy-y^2}=3\left(x-y\right)\end{matrix}\right.\)
giải hpt: a,\(\left\{{}\begin{matrix}x+y-\sqrt{xy}=3\\\sqrt{x+1}+\sqrt{y+1}=4\end{matrix}\right.\) b,\(\left\{{}\begin{matrix}x+y=5+\sqrt{\left(x-1\right)\left(y-1\right)}\\\sqrt{x-1}+\sqrt{y-1}=3\end{matrix}\right.\)
