mình không biết đã làm đúng chưa nên mong bạn thông cảm nha
1: Ta có: \(P=\left(\dfrac{x+3}{x-1}+\dfrac{\sqrt{x}}{1-\sqrt{x}}+\dfrac{1}{1+\sqrt{x}}\right)\left(\dfrac{x\sqrt{x}-1}{\sqrt{x}-1}+\sqrt{x}\right)\)
\(=\dfrac{x+3-\sqrt{x}\left(\sqrt{x}+1\right)+\sqrt{x}-1}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}\left(x+\sqrt{x}+1+\sqrt{x}\right)\)
\(=\dfrac{x+\sqrt{x}+2-x-\sqrt{x}}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}\cdot\left(\sqrt{x}+1\right)^2\)
\(=\dfrac{\left(\sqrt{x}+2\right)\left(\sqrt{x}+1\right)}{\sqrt{x}-1}\)