\(3 x ( x ^2 − 4 ) = 0\)
\(3x=0 hoặc x^2-4=0\)
\(x=0 hoặc x^2=+-2\)
\(3x=0hoặcx^2-4=0\)
\(x=0hoặc\left(x-2\right)\left(x+2\right)=0\)
\(\begin{matrix}x=0\\x-2=0\\x+2=0\end{matrix}\\ \begin{matrix}x=0\\x=2\\x=-2\end{matrix}\)
\(3x\left(x^2-4\right)=0\\ \Leftrightarrow\left\{{}\begin{matrix}3x=0\\x^2-4=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0\\\left[{}\begin{matrix}x-2=0\\x+2=0\end{matrix}\right.\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0\\\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\end{matrix}\right.\)
