\(=\left(\dfrac{\sqrt{a}}{\sqrt{a}\left(\sqrt{a}-1\right)}-\dfrac{\sqrt{a}-1}{\sqrt{a}\left(\sqrt{a}-1\right)}\right):\left(\dfrac{\left(\sqrt{a}+1\right)\left(\sqrt{a}-1\right)}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-1\right)}-\dfrac{\left(\sqrt{a}+1\right)\left(\sqrt{a}-2\right)}{\left(\sqrt{a}-1\right)\left(\sqrt{a}-2\right)}\right)\)
=\(\dfrac{\sqrt{a}-\sqrt{a}+1}{\sqrt{a}\left(\sqrt{a}-1\right)}:\left(\dfrac{a-1}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-1\right)}-\dfrac{a-\sqrt{a}-2}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-1\right)}\right)\)
\(=\dfrac{1}{\sqrt{a}\left(\sqrt{a}-1\right)}.\dfrac{\left(\sqrt{a}-2\right)\left(\sqrt{a}-1\right)}{a-1-a+\sqrt{a}+2}\)
\(=\dfrac{1}{\sqrt{a}\left(\sqrt{a}-1\right)}.\dfrac{\left(\sqrt{a}-2\right)\left(\sqrt{a}-1\right)}{\sqrt{a}+1}\)
\(=\dfrac{\sqrt{a}-2}{\sqrt{a}\left(\sqrt{a}+1\right)}=\dfrac{\sqrt{a}-2}{a+\sqrt{a}}\)
2, \(\left(\dfrac{1}{1-\sqrt{x}}-\dfrac{1}{1+\sqrt{x}}\right).\left(\dfrac{1}{\sqrt{x}}+1\right)\)
\(=\left(\dfrac{1+\sqrt{x}}{\left(1+\sqrt{x}\right)\left(1-\sqrt{x}\right)}-\dfrac{1-\sqrt{x}}{\left(1+\sqrt{x}\right)\left(1-\sqrt{x}\right)}\right)\left(\dfrac{1+\sqrt{x}}{\sqrt{x}}\right)\)
\(=\dfrac{1+\sqrt{x}-1+\sqrt{x}}{\left(1+\sqrt{x}\right)\left(1-\sqrt{x}\right)}.\dfrac{1+\sqrt{x}}{\sqrt{x}}\)
\(=\dfrac{2\sqrt{x}}{\left(1+\sqrt{x}\right)\left(1-\sqrt{x}\right)}.\dfrac{1+\sqrt{x}}{\sqrt{x}}\)
\(=\dfrac{2}{1-\sqrt{x}}\)
