`a,` ` (x-4)(2x-6)=0`
`⇒` \(\left[ \begin{array}{l}x-4=0\\2x-6=0\end{array} \right.\)
`⇒` \(\left[ \begin{array}{l}x=4\\x=3\end{array} \right.\)
Vậy `x=4` hoặc `x=3`.
`b,` ` (x-1)x-(x-1).(2x-5)=0`
`⇔ (x-1)(x-2x+5)=0`
`⇔(x-1)(5-x)=0`
`⇒` \(\left[ \begin{array}{l}x-1=0\\5-x=0\end{array} \right.\)
`⇒` \(\left[ \begin{array}{l}x=1\\x=5\end{array} \right.\)
Vậy `x=1` hoặc `x=5`.
