a. \(3x^3-6x^2=0\Leftrightarrow3x^2\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}3x^2=0\\x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\end{matrix}\right.\)
b. \(x\left(x-4\right)-12x+48=0\)
\(\Leftrightarrow x\left(x-4\right)-12\left(x-4\right)=0\)
\(\Leftrightarrow\left(x-4\right)\left(x-12\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-4=0\\x-12=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=12\end{matrix}\right.\)
V.v.v.v