ĐK : x > 0
\(B=\frac{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}{\sqrt{x}\left(\sqrt{x}+1\right)}+\frac{1-\sqrt{x}}{x+\sqrt{x}}\)
\(B=\frac{x-1}{x+\sqrt{x}}+\frac{1-\sqrt{x}}{x+\sqrt{x}}\)
\(B=\frac{x-1+1-\sqrt{x}}{x+\sqrt{x}}\)
\(B=\frac{x-\sqrt{x}}{x+\sqrt{x}}\) \(=\frac{\sqrt{x}\left(\sqrt{x}-1\right)}{\sqrt{x}\left(\sqrt{x}+1\right)}=\frac{\sqrt{x}-1}{\sqrt{x}+1}\)