`(x^2-1)(x+2)(x-3)=(x-1)(x^2-4)`
`<=>x^4-3x^3+2x^3-6x^2-x^2+3x-2x+6=x^3-4x-x^2+4`
`<=>x^4-2x^3-6x^2+5x+2=0`
`<=>(x^2-3x-1)(x+2)(x-1)=0`
`<=>x=1` hoặc `x=-2` hoặc $\left \{ {{\frac{3+\sqrt[]{13}}{2}} \atop {\frac{3-\sqrt[]{13}}{2}}} \right.$
Vậy .........