Với x ≠ 1 , x > 0\(E=\left(\dfrac{1}{x-1}+\dfrac{\sqrt{x}}{\sqrt{x}\left(\sqrt{x}+1\right)}\right).\dfrac{x-1}{\sqrt{x}+3}\\ =\left(\dfrac{1\sqrt{x}+\sqrt{x}\left(\sqrt{x}-1\right)}{\sqrt{x}\left(x-1\right)}\right).\dfrac{x-1}{\sqrt{x}+3}=\dfrac{\sqrt{x}+x-\sqrt{x}}{\sqrt{x}\left(x-1\right)}.\dfrac{x-1}{\sqrt{x}+3}=\dfrac{\sqrt{x}}{\sqrt{x}+3}\)