Bài 3:
Ta có: \(P=\left(\dfrac{8-x\sqrt{x}}{2-\sqrt{x}}+2\sqrt{x}\right)\cdot\left(\dfrac{2-\sqrt{x}}{2+\sqrt{x}}\right)^2\)
\(=\left(4+2\sqrt{x}+x+2\sqrt{x}\right)\cdot\dfrac{\left(\sqrt{x}-2\right)^2}{\left(\sqrt{x}+2\right)^2}\)
\(=x-4\sqrt{x}+4\)