Question

[lư thị ngọc giao]

chứng minh rằng

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

Answer 1

[Phan Văn Hiếu]

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

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

\(=\frac{-2\sqrt{a}}{1-a}.\frac{a-1}{\sqrt{a}}=-2\)