Đáp án:
`x^3-x^2-4`
`=x^3+x^2+2x-2x^2-2x-4`
`=x(x^2+x+2)-2(x^2+x+2)`
`=(x^2+x+2)(x-2)`
`------------------`
`(8x^3-8x^2):2x=3`
`-> 4x^2-4x=3`
`-> 4x^2-4x-3=0`
`-> 4x^2-2x+6x-3=0`
`-> 2x(2x-1)+3(2x-1)=0`
`-> (2x+3)(2x-1)=0`
`->` \(\left[ \begin{array}{l}2x+3=0\\2x-1=0\end{array} \right.\)
`->` \(\left[ \begin{array}{l}x=-\dfrac{3}{2}\\x=\dfrac{1}{2}\end{array} \right.\)