4x ( x- 2019 ) - x + 2019 = 0
4 x ( x-2019) - ( x - 2019) = 0
( x - 2019)( 4x - 1) = 0
\(\left[{}\begin{matrix}x-2019=0\\4x-1=0\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=2019\\4x=1\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=2019\\x=\dfrac{1}{4}\end{matrix}\right.\)
Kết luận : \(x\)\(\in\) { \(\dfrac{1}{4}\); 2019}
\(4x\times\left(x-2019\right)-x+2019=0\)
\(4x\times\left(x-2019\right)-\left(x-2019\right)=0\)
\(\left(4x-1\right)\times\left(x-2019\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}4x-1=0\\x-2019=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}4x=0+1\\x=0+2019\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}4x=1\\x=2019\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=1:4\\x=2019\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{4}\\x=2019\end{matrix}\right.\)
Vậy \(x=\dfrac{1}{4};x=2019\)
