con cach nao khac ko vay
tai luc kt ket qua ko dung
Gọi \(\frac{1}{x-2y}=\)a ; \(\frac{1}{x+2y}=\)b
\(\left\{{}\begin{matrix}4a-a=1\\20b+3a=1\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}3a=1\\3a+20b=1\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}a=\frac{1}{3}\\b=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\frac{1}{x-2y}=\frac{1}{3}\\\frac{1}{x+2y}=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x-2y=3\\x+2y=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}2x=3\\x+2y=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=\frac{3}{2}\\y=-3\end{matrix}\right.\)
Bạn thử thay vào coi đúng ko