\(B=\left(\frac{1}{\sqrt{x}-1}-\frac{\sqrt{x}+1}{x+2\sqrt{x}+1}\right):\frac{1}{\sqrt{x}+1}\)
\(B=\left(\frac{1}{\sqrt{x}-1}-\frac{\sqrt{x}+1}{\left(\sqrt{x}+1\right)^2}\right)\cdot\sqrt{x}+1\)
\(B=\frac{\sqrt{x}+1}{\sqrt{x}-1}-\frac{\sqrt{x}+1}{\sqrt{x}+1}=\frac{\sqrt{x}+1}{\sqrt{x}-1}-1\)
\(B=\frac{\sqrt{x}+1-\sqrt{x}+1}{\sqrt{x}-1}=\frac{2}{\sqrt{x}-1}\)