\(x^2+x=0\\ \Leftrightarrow x\left(x+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)
`x^2+x =0`
`-> x(x+1) =0`
`-> x =0` hoặc `x+1 =0`
`-> x =0` hoặc `x = -1`
Vậy `x \in {0 ; -1}`
`x^2 + x = 0`
`x.(x + 1) = 0`
`=>` \(\left[{}\begin{matrix}x=0\\x+1=0\end{matrix}\right.\) `=>` \(\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)
Vậy...
\(=\)\(\text{x(x+1)=0}\)
\(\Leftrightarrow\text{x=0,−1 }\)x2 + x = 0
=> x(x+1) = 0
=> \(\left[{}\begin{matrix}x=0\\x+1=0\end{matrix}\right.=>\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)
Vậy x = 0 hoặc x = -1
\(\Leftrightarrow x\left(x+1\right)=0\Leftrightarrow\left[{}\begin{matrix}x=0\\x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)
`x^2 + x = 0`
`=> x(x + 1) = 0`
`=>`\(\left[{}\begin{matrix}x=0\\x+1=0\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=0\\x=0-1\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)