a/ ĐKXĐ: \(x>0;x\ne1\)
b/Ta có : P\(=\left(\frac{1}{1-\sqrt{x}}-\frac{1}{1+\sqrt{x}}\right).\frac{x-1}{\sqrt{x}}\)
\(=\frac{1+\sqrt{x}-1+\sqrt{x}}{\left(1-\sqrt{x}\right)\left(1+\sqrt{x}\right)}.\frac{x-1}{\sqrt{x}}\)
\(=\frac{2\sqrt{x}}{1-x}.\frac{x-1}{\sqrt{x}}\)
\(=-2\)
Vậy P\(=-2\) khi \(x>0;x\ne1\)
Chúc bạn học tốt!