Question

Giúp mình 5;6 với 

Answer 1

Bài 5
\(=\left(\dfrac{\sqrt{a}}{\sqrt{a}-2}+\dfrac{a}{\sqrt{a}-2}\right):\dfrac{\sqrt{a}+1}{\left(\sqrt{a}-2\right)^2}=\dfrac{\sqrt{a}\left(\sqrt{a}+1\right)}{\sqrt{a}-2}.\dfrac{\left(\sqrt{a}-2\right)^2}{\sqrt{a}+1}\)
\(=\sqrt{a}\left(\sqrt{a}-2\right)=a-2\sqrt{a}\)