Question

Giải bài toán giúp mình nhé

Answer 1

a: \(\Leftrightarrow\left\{{}\begin{matrix}3x-2y=-1\\8x-2y=4\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}-5x=-5\\4x-y=2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\y=2\end{matrix}\right.\)

b: \(\Leftrightarrow\left\{{}\begin{matrix}4x+8y=-4\\4x+3y=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}5y=-5\\x+2y=-1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=-1\\x=1\end{matrix}\right.\)

c: \(\Leftrightarrow\left\{{}\begin{matrix}3x-6y=-12\\-3x+6y=10\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}0x=-2\left(loại\right)\\-3x+6y=10\end{matrix}\right.\Leftrightarrow\left(x,y\right)\in\varnothing\)

d: \(\Leftrightarrow\left\{{}\begin{matrix}2x+y=-2\\2x+y=-2\end{matrix}\right.\Leftrightarrow\left(x,y\right)\in R\)

Answer 2

\(a,\left\{{}\begin{matrix}3x-2y=-1\\4x-y=2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}3x-2\left(4x-2\right)=-1\\y=4x-2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}3x-8x+4=-1\\y=4x-2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}-5x=-5\\y=4x-2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\y=4.1-2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\y=2\end{matrix}\right.\)

\(b,\left\{{}\begin{matrix}x+2y=-1\\4x+3y=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-1-2y\\4\left(-1-2y\right)+3y=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-1-2y\\-4-8y+3y=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-1-2y\\-5y=5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-1-2\left(-1\right)\\y=-1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\y=-1\end{matrix}\right.\)

\(c,\left\{{}\begin{matrix}x-2y=-4\\-3x+6y=10\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=2y-4\\-3\left(2y-4\right)+6y=10\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=2y-4\\-6y+12+6y=10\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=2y-4\\12=10\left(vô.lí\right)\end{matrix}\right.\)

\(d,\left\{{}\begin{matrix}2x+y=-2\\4x+2y=-4\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2x+y=-2\\2x+y=-2\left(luôn.đúng\right)\end{matrix}\right.\)