\(A=\dfrac{x+2}{x\sqrt{x}+1}+\dfrac{\sqrt{x}-1}{x-\sqrt{x}+1}-\dfrac{\sqrt{x}-1}{x-1}\)
\(=\dfrac{x+2+x-1-x+\sqrt{x}-1}{\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)}\)
\(=\dfrac{\sqrt{x}\left(\sqrt{x}+1\right)}{\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)}=\dfrac{\sqrt{x}}{x-\sqrt{x}+1}\)
\(A-1=\dfrac{\sqrt{x}-x+\sqrt{x}-1}{x-\sqrt{x}+1}=\dfrac{-\left(\sqrt{x}-1\right)^2}{x-\sqrt{x}+1}< 0\)
=>A<1