a) ĐKXĐ \(\left\{{}\begin{matrix}x\ge0\\x\ne1\end{matrix}\right.\)
\(\frac{1-x\sqrt{x}}{1-\sqrt{x}}=\frac{1-\sqrt{x^3}}{1-\sqrt{x}}=\frac{\left(1-\sqrt{x}\right)\left(1+\sqrt{x}+x\right)}{1-\sqrt{x}}=x+\sqrt{x}+1\)
b) ĐKXĐ: \(\left\{{}\begin{matrix}a,b\ge0\\a\ne b\end{matrix}\right.\)
\(\frac{a-2\sqrt{ab}+b}{\sqrt{a}-\sqrt{b}}+2\sqrt{ab}=\frac{\left(\sqrt{a}-\sqrt{b}\right)^2}{\sqrt{a}-\sqrt{b}}+2\sqrt{ab}=\sqrt{a}-\sqrt{b}+2\sqrt{ab}\)