\(x^2+x-6=0\Leftrightarrow\left(x-2\right)\left(x+3\right)=0\Leftrightarrow\left[{}\begin{matrix}x-2=0\\x+3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-3\end{matrix}\right.\)
Cho đa thức `=0`
`->x^{2}+x-6=0`
`->(x^{2}+3x)-(2x+6)=0`
`->x(x+3)-2(x+3)=0`
`->(x+3)(x-2)=0`
`->x+3=0` hay `x-2=0`
`->x=-3` hay `x=2`
Ta có: \(x^2+x-6=0\)
\(\Leftrightarrow\left(x+3\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=2\end{matrix}\right.\)