Question

[Nguyễn Châu Mỹ Linh]

Giải phương trình:

1. \(\left\{{}\begin{matrix}4x-2y=3\\6x-3y=5\end{matrix}\right.\)

2. \(\left\{{}\begin{matrix}2x-3y=5\\4x+6y=10\end{matrix}\right.\)

3. \(\left\{{}\begin{matrix}3x-4y+2=0\\5x+2y=14\end{matrix}\right.\)

4. \(\left\{{}\begin{matrix}2x+5y=3\\3x-2y=14\end{matrix}\right.\)

Answer 1

[nguyen thi vang]

1) \(\left\{{}\begin{matrix}3x-2y=4\\4x+2y=10\end{matrix}\right.\)

<=> \(\left\{{}\begin{matrix}3x-2y=4\\7x=14\end{matrix}\right.< =>\left\{{}\begin{matrix}x=2\\y=1\end{matrix}\right.\)

2)\(\left\{{}\begin{matrix}2x+3y=5\\4x+6y=10\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}4x+6y=10\\4x=6y=10\end{matrix}\right.\)

=> Hệ có vô số nghiệm.

3)\(\left\{{}\begin{matrix}3x-4y=-2\\10x+4y=28\end{matrix}\right.\)

<=>\(\left\{{}\begin{matrix}3x-4y=-2\\13x=26\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=2\\y=2\end{matrix}\right.\)

4)\(\left\{{}\begin{matrix}6x+15y=9\\6x-4y=28\end{matrix}\right.\)

<=>\(\left\{{}\begin{matrix}6x+15y=9\\19y=19\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=4\\y=-1\end{matrix}\right.\)