`3x^2-9x=0`
`<=>3x(x-3)=0`
`<=>x=0` hoặc `x=3`
Vậy `S={0;3}`
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`x(x-6)+10(x-6)=0`
`<=>(x-6)(x+10)=0`
`<=>x=6` hoặc `x=-10`
Vậy `S={-10;6}`
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`x(x-4)+x-4=0`
`<=>(x-4)(x+1)=0`
`<=>x=4` hoặc `x=-1`
Vậy `S={-1;4}`
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`x(x-4)=2x-8`
`<=>x(x-4)-2(x-4)=0`
`<=>(x-4)(x-2)=0`
`<=>x=4` hoặc `x=2`
Vậy `S={4;2}`
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`(2x+3)(x-1)+(2x-3)(1-x)=0`
`<=>(2x+3)(x-1)-(2x-3)(x-1)=0`
`<=>(x-1)(2x+3-2x+3)=0`
`<=>(x-1).6=0`
`<=>x-1=0`
`<=>x=1`
Vậy `S={1}`