Phân tích các đa thức sau thành nhân tử: x^3 + 2 - 2x^2 -x

* Hướng dẫn giải

$\begin{array}{l}{\mathrm{x}}^3+2-2{\mathrm{x}}^2-\mathrm{x}=({\mathrm{x}}^3-\mathrm{x})-(2{\mathrm{x}}^2-2)\\ \mathrm{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}}=\mathrm{x}({\mathrm{x}}^2-1)-2({\mathrm{x}}^2-1)=({\mathrm{x}}^2-1)(\mathrm{x}-2)=(\mathrm{x}+1)(\mathrm{x}-1)(\mathrm{x}-2)\end{array}$