`Đáp án:
Giải thích các bước giải:
a) `x( x - 2 ) + x -2 = 0`
`⇔ x(x-2)+(x-2)=0`
`⇔ (x+1)(x-2)=0`
`⇔` \(\left[ \begin{array}{l}x+1=0\\x-2=0\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=-1\\x=2\end{array} \right.\)
Vậy `S={-1;2}`
b) `5x (x-3)-x+3=0`
`⇔ 5x(x-3)-(x-3)=0`
`⇔ (5x-1)(x-3)=0`
`⇔` \(\left[ \begin{array}{l}5x-1=0\\x-3=0\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=\dfrac{1}{5}\\x=3\end{array} \right.\)
Vậy `S={1/5;3}`
