\(\frac{1-a\sqrt{a}}{1-\sqrt{a}}=\frac{\left(1-a\sqrt{a}\right)\left(1+\sqrt{a}\right)}{\left(1-\sqrt{a}\right)\left(1+\sqrt{a}\right)}=\frac{1+\sqrt{a}-a\sqrt{a}-a^2}{1-a}=\frac{\left(1-a\right)\left(1+a\right)+\sqrt{a}\left(1-a\right)}{1-a}\)
\(=\frac{\left(1-a\right)\left(1+a-\sqrt{a}\right)}{1-a}=1+a+\sqrt{a}\)