Rút gọn phân thức: x^3 - 2x^2 + x/ 7x^3 - 7x^2

* Hướng dẫn giải

$\frac{{\mathrm{x}}^3-2{\mathrm{x}}^2+\mathrm{x}}{7{\mathrm{x}}^3-7{\mathrm{x}}^2}=\frac{\mathrm{x}\left({\mathrm{x}}^2-2\mathrm{x}+1\right)}{7{\mathrm{x}}^2\left(\mathrm{x}-1\right)}=\frac{\mathrm{x}{\left(\mathrm{x}-1\right)}^2}{7{\mathrm{x}}^2\left(\mathrm{x}-1\right)}=\frac{\mathrm{x}-1}{7\mathrm{x}}$