Đáp án + Giải thích các bước giải:
`a)` `(x-2)(3x-1)=x(2-x)`
`<=>3x^2-x-6x+2=2x-x^2`
`<=>3x^2-x-6x+2-2x+x^2=0`
`<=>4x^2-9x+2=0`
`<=>4x^2-8x-x+2=0`
`<=>4x(x-2)-(x-2)=0`
`<=>(x-2)(4x-1)=0`
`<=>`\(\left[ \begin{array}{l}x=2\\x=\dfrac{1}{4}\end{array} \right.\)
Vậy `S={2;1/4}`
`b)` `(x+1)/3+1=3-(5x)/10`
`<=>[10(x+1)]/30+30/30=90/30-(5x*3)/30`
`=>10(x+1)+30=90-15x`
`<=>10x+10+30-90+15x=0`
`<=>25x-50=0`
`<=>25x=50`
`<=>x=2`
Vậy `S={2}`.