Question

bài 1

a)\(\left\{{}\begin{matrix}-x+3y=10\\x-5y=16\end{matrix}\right.\)

b)\(\left\{{}\begin{matrix}2x+y=7\\-x+4y=10\end{matrix}\right.\)

c)\(\left\{{}\begin{matrix}3x-5y=-18\\x+2y=5\end{matrix}\right.\)

Answer 1

a)\(\left\{{}\begin{matrix}-2y=-6\\x-5y=16\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=3\\x=16+5y\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}y=3\\x=31\end{matrix}\right.\)

Answer 2

b)\(\left\{{}\begin{matrix}2x+y=7\\-2x+8y=20\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}9y=27\\-2x+8y=20\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}y=3\\-2x=20-8y\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}y=3\\x=2\end{matrix}\right.\)

Answer 3

a)\(\left\{{}\begin{matrix}-x+3y=10\\x-5y=16\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}-2y=26\\x-5y=16\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}y=-13\\x-5.\left(-13\right)=16\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}y=-13\\x=-49\end{matrix}\right.\)