\(M=\left(1-\dfrac{4\sqrt{x}}{x-1}+\dfrac{1}{\sqrt{x}+1}\right):\left(\dfrac{x-2\sqrt{x}}{x-1}\right)=\dfrac{x-1-4\sqrt{x}+\sqrt{x}-1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}:\dfrac{x-2\sqrt{x}}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}=\dfrac{x-3\sqrt{x}-2}{x-2\sqrt{x}}\)