\(P=\left(\dfrac{\sqrt{x}-2}{x-4}+\dfrac{\sqrt{x}+2}{x-4}\right).\dfrac{\sqrt{x}\left(\sqrt{x}-2\right)}{2}\)
\(=\left(\dfrac{\sqrt{x}-2+\sqrt{x}+2}{x-4}\right).\dfrac{\sqrt{x}\left(\sqrt{x}-2\right)}{2}\)
\(=\dfrac{2\sqrt{x}.\sqrt{x}.\left(\sqrt{x}-2\right)}{2.\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}=\dfrac{x}{\sqrt{x}+2}\)