\(\hept{\begin{cases}\left(m-1\right)x-my=3m-1\\2x-\left(m+3\right)=y\end{cases}\Leftrightarrow\hept{\begin{cases}\left(m-1\right)x-m\left(2x-\left(m+3\right)\right)=3m-1\\2x-\left(m+3\right)=y\end{cases}}}\)
\(\Leftrightarrow\hept{\begin{cases}\left(m-1\right)x-2mx+m\left(m+3\right)=3m\\y=2x-\left(m+3\right)\end{cases}}\Leftrightarrow\hept{\begin{cases}x\left(-m-1\right)=-m^2-2m\\y=2x-\left(m+3\right)\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x\left(m+1\right)=\left(m+1\right)^2\\y=2x-\left(m+3\right)\end{cases}\Leftrightarrow\hept{\begin{cases}x=m+1\Rightarrow y=m-3\\m=-1\Rightarrow x;y\left(\text{loai}\right)\end{cases}}}\)
\(\Rightarrow\hept{\begin{cases}x=m+1\\y=m-3\end{cases}}\)
\(\Rightarrow x^2+y^2< 4\Leftrightarrow\left(m+1\right)^2-\left(m-3\right)^2< 4\)
\(\Leftrightarrow8m< 12\)
\(\Leftrightarrow m< 3/2\)
*P/s: T trả đấy!*
