a)P= \(\left(\frac{1}{\sqrt{x}}+\frac{\sqrt{x}}{\sqrt{x}+1}\right):\frac{\sqrt{x}}{x+\sqrt{x}}\)
\(\Leftrightarrow\frac{\sqrt{x}+1+x}{\sqrt{x}\left(\sqrt{x}+1\right)}.\left(\sqrt{x}+1\right)\)
\(\Leftrightarrow\frac{x+\sqrt{x}+1}{\sqrt{x}}\)
b) \(P=-1\Leftrightarrow\frac{x+\sqrt{x}+1}{\sqrt{x}}=1\)
\(\Leftrightarrow x+\sqrt{x}+1=\sqrt{x}\)
\(\Leftrightarrow x+1=0\)
\(\Rightarrow x=1\left(t/m\right)\)