$\begin{array}{l}B = \left(\dfrac{\sqrt x - 2}{x - 1}-\dfrac{2 + \sqrt x}{x + 2\sqrt x +1}\right)\cdot\dfrac{\sqrt x + 1}{\sqrt x}\\ \to B = \dfrac{\sqrt x-2}{(\sqrt x - 1)(\sqrt x +1)}\cdot \dfrac{\sqrt x + 1}{\sqrt x} - \dfrac{2 + \sqrt x}{(\sqrt x + 1)^2}\cdot\dfrac{\sqrt x +1}{\sqrt x}\\ \to B = \dfrac{\sqrt x - 2}{\sqrt x(\sqrt x - 1)}- \dfrac{\sqrt x+2}{\sqrt x(\sqrt x+1)}\\ \to B = \dfrac{(\sqrt x - 2)(\sqrt x + 1) - (\sqrt x + 2)(\sqrt x-1)}{\sqrt x(\sqrt x - 1)(\sqrt x +1)}\\ \to B = \dfrac{x - \sqrt x - 2 - (x + \sqrt x - 2)}{\sqrt x(\sqrt x - 1)(\sqrt x +1)}\\ \to B = \dfrac{-2\sqrt x}{\sqrt x(\sqrt x - 1)(\sqrt x +1)}\\ \to B = \dfrac{-2}{(\sqrt x - 1)(\sqrt x +1)}\\ \end{array}$
