Rút gọn phân thức : 2x^3 +x^2 -2x -1/ x^3 + 2x^2 -x -2

* Hướng dẫn giải

$\frac{2{\mathrm{x}}^3+{\mathrm{x}}^2-2\mathrm{x}-1}{{\mathrm{x}}^3+2{\mathrm{x}}^2-\mathrm{x}-2}=\frac{{\mathrm{x}}^2.\left(2\mathrm{x}+1\right)-\left(2\mathrm{x}+1\right)}{{\mathrm{x}}^2.\left(\mathrm{x}+2\right)-\left(\mathrm{x}+2\right)}=\frac{\left({\mathrm{x}}^2-1\right)\left(2\mathrm{x}+1\right)}{\left({\mathrm{x}}^2-1\right)\left(\mathrm{x}+2\right)}=\frac{2\mathrm{x}+1}{\mathrm{x}+2}$