\(P=\left(\dfrac{a+2\sqrt{a}}{\sqrt{a}+2}-1\right):\left(\dfrac{a-\sqrt{a}}{\sqrt{a}-1}+1\right)\)
\(=\left[\dfrac{\sqrt{a}\left(\sqrt{a}+2\right)}{\sqrt{a}+2}-1\right]:\)\(\left[\dfrac{\sqrt{a}\left(\sqrt{a}-1\right)}{\sqrt{a}-1}+1\right]\)
\(=\dfrac{\sqrt{a}-1}{\sqrt{a}+1}\)