`a)` `-3x(3x+1)+(3x-1)^2=2(3-4x)`
`=> -9x^2-3x+9x^2-6x+1-6+8x=0`
`=>-x-5=0`
`=>x=-5`
`b)` `x(x-2)+(x-2)=0`
`=>(x+2)(x+1)=0`
`=>x+2=0` hoặc `x+1=0`
`=>x=-2` hoặc` x=-1`
`c)` `5x(x-2)+3x-6=0`
`=>5x(x-2)+3(x-2)`
`=>(x-2)(5x+3)=0`
`=>x-2=0` hoặc `5x+3=0`
`=>x=2` hoặc `x=-3/5`
`d)` `x^2-3x+2=0`
`=>x^2-x-2x+2=0`
`=>x(x-1)-2(x-1)=0`
`=>(x-2)(x-1)=0`
`=>x-2=0` hoặc `x-1=0`
`=>x=2` hoặc `x=1`