Question

Giải bài 2b giùm mk

Answer 1

\(\left\{{}\begin{matrix}mx-y=2\\3x+my=5\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}m^2x-my=2m\\3x+my=5\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}\left(m^2+3\right)x=2m+5\\y=mx-2\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}x=\frac{2m+5}{m^2+3}\\y=\frac{5m-6}{m^2+3}\end{matrix}\right.\)

Để \(\left\{{}\begin{matrix}x>0\\y< 0\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}\frac{2m+5}{m^2+3}>0\\\frac{5m-6}{m^2+3}< 0\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}2m+5>0\\5m-6< 0\end{matrix}\right.\) \(\Rightarrow-\frac{5}{2}< m< \frac{6}{5}\)

Answer 2