Question

giai bang pp cong dai so

{x-3y=-2

{2x+y=3

Answer 1

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

\(\Leftrightarrow\left\{{}\begin{matrix}2x-6y=-4\\2x+y=3\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}-7y=-7\\2x+y=3\end{matrix}\right.\)

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

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

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

Vậy hệ phương trình có nghiệm duy nhất là \(\left(1;1\right)\).

Answer 2

{x−3y=−22x+y=3<=>{x−3(3−2x)=−2y=3−2x<=>{7x=7y=3−2x<=>{x=1y=3−2.1<=>{x=1y=1

Answer 3

\(\left\{{}\begin{matrix}x-3y=-2\\2x+y=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2x-6y=-4\\2x+y=3\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}-7y=-7\\2x+y=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\y=1\end{matrix}\right.\)

Answer 4

\(\left\{{}\begin{matrix}x-3y=-2\\2x+y=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2x-6y=-4\\2x+y=3\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}-7y=-7\\2x+y=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\y=1\end{matrix}\right.\)