Question

giải hệ pt: \(\left\{{}\begin{matrix}\dfrac{x+1}{x-1}-\dfrac{5y}{y+2}=9\\\dfrac{2}{x-1}-\dfrac{5}{y+2}=4\end{matrix}\right.\)

Answer 1

\(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{x-1+2}{x-1}-\dfrac{5y+10-10}{y+2}=9\\\dfrac{2}{x-1}-\dfrac{5}{y+2}=4\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{2}{x-1}+1-5+\dfrac{10}{y+2}=9\\\dfrac{2}{x-1}-\dfrac{5}{y+2}=4\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{2}{x-1}+\dfrac{10}{y+2}=9+5-1=14-1=13\\\dfrac{2}{x-1}-\dfrac{5}{y+2}=4\end{matrix}\right.\)

=>x-1=2/7; y+2=5/3

=>x=9/7; y=-1/3