`a, 4x(x+1)=8(x+1)`
`⇔4x(x+1)-8(x+1)=0`
`⇔(x+1)(4x-8)=0`
`<=>x=-1` hoặc `x=2`
`b, x(x-1)-2(1-x)=0`
`⇔ x(x-1)+2(x-1)=0`
`⇔ (x+2)(x-1)=0`
`⇔` `x=-2` hoặc `x=1`
`c, 2x(x-2)-(2-x)=0` `⇔ 2x(x-2)+(x-2)=0` `⇔ (2x+1)(x-2)=0` `⇔x=-1/2` hoặc `x=2`
`d, (x-3) +3-x=0` `⇔x-3 + 3-x=0` `⇔0=0` `=>` Pt vô số no
`g, 5x(x-2000) - x+2000=0` `⇔5x(x-2000)-(x-2000)=0` `⇔(5x-1)(x-2000)=0` `⇔` `x=-1/5` hoặc `x=2000`
`h, x - 4x = 0` `⇔ x = 0`
`k, (1-x) - 1+x=0` `⇔1-x-1+x=0` `⇔0=0` `⇔` Pt vô số no.
`m, x +6x = 0` `⇔ x=0`
Vậy .......................................