$\frac{1-a\sqrt{a}}{1\sqrt{a}}$ 

`-` Nhân `:` `1*` $\sqrt{a}$ `=` $\sqrt{a}$

`=` $\frac{1-a\sqrt{a}}{\sqrt{a}}$ 

`-` Hữu tỉ hoá $\frac{1-a\sqrt{a}}{\sqrt{a}}$ `:` $\frac{\sqrt{a}(-a\sqrt{a}+1)}{a}$ 

`=` $\frac{\sqrt{a}(-a\sqrt{a}+1)}{a}$