a: Ta có: \(Q=\sqrt{x}\left(\dfrac{\sqrt{x}+1}{x+\sqrt{x}+1}+\dfrac{1}{1-\sqrt{x}}+\dfrac{x+2}{x\sqrt{x}-1}\right)\)
\(=\sqrt{x}\left(\dfrac{x-1-x-\sqrt{x}-1+x+2}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\right)\)
\(=\sqrt{x}\left(\dfrac{x-\sqrt{x}}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\right)\)
\(=\dfrac{x}{x+\sqrt{x}+1}\)