Giải phương trình sau đây
b: \(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{2}{x+1}-2\sqrt{y-1}=-2\\\dfrac{3}{x+1}+2\sqrt{y-1}=7\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\dfrac{5}{x+1}=5\\\sqrt{y-1}=2\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x+1=1\\y-1=4\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0\\y=5\end{matrix}\right.\)
c: \(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{3}{x-y+1}-\dfrac{4}{x+2y}=-7\\\dfrac{8}{x-y+1}+\dfrac{4}{x+2y}=-4\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x-y+1=-1\\x+2y=1\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x-y=-2\\x+2y=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}-3y=-3\\x-y=-2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=1\\x=-1\end{matrix}\right.\)
