Question

làm giúp mik câu 3 với ạ

l

Answer 1

3:

a: \(A=\dfrac{\sqrt{x}\left(\sqrt{x}+2\right)+\sqrt{x}\left(\sqrt{x}-2\right)-x+2\sqrt{x}}{x-4}\)

\(=\dfrac{x+2\sqrt{x}+x-2\sqrt{x}-x+2\sqrt{x}}{x-4}\)

\(=\dfrac{x+2\sqrt{x}}{x-4}=\dfrac{\sqrt{x}}{\sqrt{x}-2}\)

b: Khi x=4-2căn 3 thì \(A=\dfrac{\sqrt{3}-1}{\sqrt{3}-1-2}=\dfrac{\sqrt{3}-1}{\sqrt{3}-3}=\dfrac{-1}{\sqrt{3}}\)