=\(\left(\dfrac{\sqrt{x}}{3+\sqrt{x}}+\dfrac{9+x}{\left(3-\sqrt{x}\right).\left(3+\sqrt{x}\right)}\right).\left(3\sqrt{x}-x\right)\)
=\(\left(\dfrac{\sqrt{x}.\left(3-\sqrt{x}\right)}{\left(3+\sqrt{x}\right)\left(3-\sqrt{x}\right)}+\dfrac{9+x}{\left(3+\sqrt{x}\right)\left(3-\sqrt{x}\right)}\right).\left(3\sqrt{x}-x\right)\)
=\(\dfrac{3\sqrt{x}-x+9+x}{\left(3+\sqrt{x}\right)\left(3-\sqrt{x}\right)}.\left(3\sqrt{x}-x\right)\)
=\(\dfrac{3\sqrt{x}+9}{\left(3+\sqrt{x}\right)\left(3-\sqrt{x}\right)}.\left(3\sqrt{x}-x\right)\)
=\(\dfrac{3\left(\sqrt{x}+3\right).\sqrt{x}\left(3-\sqrt[]{x}\right)}{\left(3+\sqrt{x}\right)\left(3-\sqrt{x}\right)}\)
=\(3\sqrt{x}\)
