a) \(3x^3-3x=0\)
\(\Rightarrow3x\left(x^2-1\right)=0\)
\(\Rightarrow3x\left(x-1\right)\left(x+1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}3x=0\\x-1=0\\x+1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0\\x=1\\x=-1\end{matrix}\right.\)
Vậy \(x\in\left\{0;\pm1\right\}\)
b) \(x\left(x-2\right)+x-2=0\)
\(\Rightarrow x\left(x-2\right)+\left(x-2\right)=0\)
\(\Rightarrow\left(x+1\right)\left(x-2\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x+1=0\\x-2=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-1\\x=2\end{matrix}\right.\)
Vậy \(x\in\left\{-1;2\right\}\)
c) \(5x\left(x-2000\right)-x+2000=0\)
\(\Rightarrow5x\left(x-2000\right)-\left(x-2000\right)=0\)
\(\Rightarrow\left(5x-1\right)\left(x-2000\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}5x-1=0\\x-2000=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{5}\\x=2000\end{matrix}\right.\)
Vậy \(x\in\left\{\dfrac{1}{5};2000\right\}\)
