ĐKXĐ : \(\left\{{}\begin{matrix}2x-1>0\\y+2>0\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x>\dfrac{1}{2}\\y>-2\end{matrix}\right.\)
PT ( I ) \(\Leftrightarrow\left(\sqrt{\dfrac{2x-1}{y+2}}+\sqrt{\dfrac{y+2}{2x-1}}\right)^2=4\)
\(\Leftrightarrow\dfrac{2x-1}{y+2}+\dfrac{y+2}{2x-1}+2\sqrt{\left(\dfrac{2x-1}{y+2}\right)\left(\dfrac{y+2}{2x-1}\right)}=4\)
\(\Leftrightarrow\dfrac{2x-1}{y+2}+\dfrac{y+2}{2x-1}=2\)
Từ PT ( II ) ta được : \(x=12-y\)
- Thế x vào PT trên ta được : \(\dfrac{2\left(12-y\right)}{y+2}+\dfrac{y+2}{2\left(12-y\right)}=2\)
\(\Leftrightarrow4\left(y-12\right)^2+\left(y+2\right)^2=4\left(12-y\right)\left(y+2\right)\)
\(\Leftrightarrow4\left(y^2-24y+144\right)+y^2+4y+4=4\left(12y+24-y^2-2y\right)\)
\(\Leftrightarrow4y^2-96y+576+y^2+4y+4-40y-96+4y^2=0\)
\(\Leftrightarrow9y^2-132y+484=0\)
\(\Leftrightarrow y=\dfrac{22}{3}\left(TM\right)\)
- Thay lại vào PT ta được : \(x=\dfrac{14}{3}\)
Vậy phương trình có nghiệm là \(S=\left\{\left(\dfrac{22}{3};\dfrac{14}{3}\right);\left(\dfrac{14}{3};\dfrac{22}{3}\right)\right\}\)
