5x(x-2000)-(x-2000)=0
(x-2000)(5x-1)=0
\(\left[{}\begin{matrix}x-2000=0\\5x-1=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2000\\5x=1\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2000\\x=\dfrac{1}{5}\end{matrix}\right.\)