Question

[Lê Hồng Nguyên]

ai lam ho tui 3 cau dc ko,chua nghi dc 

Answer 1

[Nguyễn Huy Tú]

\(\hept{\begin{cases}6x+\frac{9}{y-2}=9\\6x-\frac{2}{y-2}=20\end{cases}}\Leftrightarrow\hept{\begin{cases}-\frac{11}{y-2}=11\\2x=3-\frac{3}{y-2}\end{cases}}\Leftrightarrow\hept{\begin{cases}y-2=-1\\2x=3-\frac{3}{-1}=6\end{cases}}\Leftrightarrow\hept{\begin{cases}y=1\\x=3\end{cases}}\)

Answer 2

[Nguyễn Huy Tú]

\(\hept{\begin{cases}2xy+5x-6y-15=2xy-2x+7y-7\\12xy-24x-3y+6=12xy+18x-2y-3\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}5x-6y-15=-2x+7y-7\\-24x-3y+6=18x-3y-3\end{cases}}\Leftrightarrow\hept{\begin{cases}7x-13y=8\\-42x=-9\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}y=\frac{7x-8}{13}\\x=\frac{3}{14}\end{cases}}\Leftrightarrow\hept{\begin{cases}y=-\frac{1}{2}\\x=\frac{3}{14}\end{cases}}\)