Bạn chưa đăng nhập. Vui lòng đăng nhập để hỏi bài
Vy Pham

\(\left\{{}\begin{matrix}\dfrac{2x}{x+1}+\dfrac{y}{y+1}=2\\\dfrac{x}{x+1}+\dfrac{3y}{y+1}=-1\end{matrix}\right.\)

ILoveMath
17 tháng 1 2022 lúc 21:49

ĐKXĐ:\(\left\{{}\begin{matrix}x\ne-1\\y\ne-1\end{matrix}\right.\)

\(\left\{{}\begin{matrix}\dfrac{2x}{x+1}+\dfrac{y}{y+1}=2\\\dfrac{x}{x+1}+\dfrac{3y}{y+1}=-1\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{2x}{x+1}+\dfrac{y}{y+1}=2\\\dfrac{2x}{x+1}+\dfrac{6y}{y+1}=-2\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{2x}{x+1}+\dfrac{y}{y+1}=2\\\dfrac{2x}{x+1}+\dfrac{6y}{y+1}-\dfrac{2x}{x+1}-\dfrac{y}{y+1}=2-\left(-2\right)\end{matrix}\right.\)

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

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

\(\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{3}{2}\\y=4\end{matrix}\right.\)

 

 

 

Nguyễn Huy Tú
17 tháng 1 2022 lúc 21:51

\(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{6x}{x+1}+\dfrac{3y}{y+1}=2\\\dfrac{x}{x+1}+\dfrac{3y}{y+1}=-1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\dfrac{5x}{x+1}=3\\\dfrac{6x}{x+1}+\dfrac{3y}{y+1}=2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{3}{2}\\\dfrac{18}{5}+\dfrac{3y}{y+1}=2\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{3}{2}\\\dfrac{3y}{y+1}=-\dfrac{8}{5}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{3}{2}\\3y=-\dfrac{8}{5}y-\dfrac{8}{5}\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}x=\dfrac{3}{2}\\\dfrac{23}{5}y=-\dfrac{8}{5}\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}x=\dfrac{3}{2}\\y=-\dfrac{8}{23}\end{matrix}\right.\)


Các câu hỏi tương tự
DUTREND123456789
Xem chi tiết
Tuyết Ly
Xem chi tiết
Lizy
Xem chi tiết
DUTREND123456789
Xem chi tiết
Ngọc Mai
Xem chi tiết
tranthuylinh
Xem chi tiết
Sooun Lee
Xem chi tiết
Thanh Thanh
Xem chi tiết
tranthuylinh
Xem chi tiết