a)\( 3x . ( x- 4 ) = 0\)
\(\Rightarrow\) \(\left[{}\begin{matrix}3x=0 \\x-4=0\end{matrix}\right.\)
\(\Rightarrow\) \(\left[{}\begin{matrix}x=0\\x=4\end{matrix}\right.\)
Vậy \(x=0\) hoặc \(x=4\)
b)\(( x- 2 ) . ( 2x - 4) =0\)
\(\Rightarrow\) \(\left[{}\begin{matrix}x-2=0\\2x-4=0\end{matrix}\right.\)
\(\Rightarrow\) \(x=2\)
Vậy \(x=2\)
:v