Bài 1: (Câu đầu trước)
Bài 1:
($\frac{1}{a - \sqrt[]{a}} + \frac{1}{\sqrt[]{a } - 1}$) : $\frac{\sqrt[]{a} + 1} {a - 2\sqrt[]{a} + 1} $ = ($\frac{1}{\sqrt[]{a}(\sqrt[]{a} - 1)} + \frac{1}{\sqrt[]{a} - 1}) : \frac{\sqrt[]{a} + 1}{(\sqrt[]{a} - 1)^2}$= ($\frac{1}{\sqrt[]{a}(\sqrt[]{a} - 1)} + \frac{\sqrt[]{a}}{\sqrt[]{a}(\sqrt[]{a} - 1)}) \frac{(\sqrt[]{a} - 1)^2}{\sqrt[]{a} + 1}$= $\frac{\sqrt[]{a} + 1}{\sqrt[]{a}(\sqrt[]{a} - 1)} . \frac{(\sqrt[]{a} - 1)^2}{\sqrt[]{a} +1}$= $\frac{\sqrt[]{a} - 1}{\sqrt[]{a}}$
:khi (72)::khi (72)::khi (72):