\(K=\left(\dfrac{1}{\sqrt{x}-1}-\dfrac{2}{x\sqrt{x}-x+\sqrt{x}-1}\right):\left(1-\dfrac{\sqrt{x}}{x+1}\right)=\left(\dfrac{x-1}{\left(x+1\right)\left(\sqrt{x}-1\right)}\right).\left(\dfrac{x+1}{x+1-\sqrt{x}}\right)=\dfrac{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}{\left(\sqrt{x}-1\right)\left(x-\sqrt{x}+1\right)}=\dfrac{\sqrt{x}+1}{x-\sqrt{x}+1}\)để rk là ok rồi