`#tnvt`
`(3x-1)^2-(3x+2)(3x-2)=0`
`<=>(3x-1)^2-(3x)^2+2^2=0`
`<=>(3x-1-3x)(3x-1+3x)=-4`
`<=>-(6x-1)=-4`
`<=>-6x+1=-4`
`<=>-6x=-5`
`<=>x=5/6`
Vậy `x=5/6`
`(2x+5)^2-(x-1)(x+1)-3x^2=0`
`<=>4x^2+20x+25-x^2+1-3x^2=0`
`<=>20=-26`
`<=>x=-13/10`
Vậy `x=-13/10`