Rút gọn để A trở nên tối giản

$x\sqrt{x}-1=\sqrt{x}^3-1=(\sqrt{x}-1)(x+\sqrt{x}+1)$

$A=\dfrac{x+2+(\sqrt{x}+1)(\sqrt{x}-1)-x-\sqrt{x}-1}{(\sqrt{x}-1)(x+\sqrt{x}+1)}$

$=\dfrac{x+2+x-1-x-\sqrt{x}-1}{(\sqrt{x}-1)(x+\sqrt{x}+1)}$

$=\dfrac{x-\sqrt{x}}{(\sqrt{x}-1)(x+\sqrt{x}+1)}$

$=\dfrac{\sqrt{x}}{x+\sqrt{x}+1}$