Phân tích đa thức sau thành nhân tử: x^3 + 2x^2 + 2x +1

* Hướng dẫn giải

$\begin{array}{l}{\mathrm{x}}^3+2{\mathrm{x}}^2+2\mathrm{x}+1\\ =\left({\mathrm{x}}^3+1\right)+\left(2{\mathrm{x}}^2+2\mathrm{x}\right)\\ =\left(\mathrm{x}+1\right)\left({\mathrm{x}}^2-\mathrm{x}+1\right)+2\mathrm{x}\left(\mathrm{x}+1\right)\\ =\left(\mathrm{x}+1\right)\left({\mathrm{x}}^2-\mathrm{x}+1+2\mathrm{x}\right)\\ =\left(\mathrm{x}+1\right)\left({\mathrm{x}}^2+\mathrm{x}+1\right)\end{array}$