`3x(x-4)-x+4=0`
`<=>3x(x-4)-(x-4)=0`
`<=>(x-4)(3x-1)=0`
`<=>[(x=4),(3x=1):}`
`<=>[(x=4),(x=1/3):}`
Vậy `S={4;1/3}`
`3x(x-4)-x+4=0`
`<=>3x(x-4)-(x-4)=0`
`<=>(3x-1)(x-4)=0`
`<=>` $\left[\begin{matrix} 3x-1=0\\ x-4=0\end{matrix}\right.$
`<=>` $\left[\begin{matrix} x=\dfrac{1}{3}\\ x=4\end{matrix}\right.$
Ta có: \(3x\left(x-4\right)-x+4=0\)
\(\Leftrightarrow3x\left(x-4\right)-\left(x-4\right)=0\)
\(\Leftrightarrow\left(x-4\right)\left(3x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=\dfrac{1}{3}\end{matrix}\right.\)
