a: \(P=\dfrac{x+\sqrt{x}+3\sqrt{x}-3-6\sqrt{x}+4}{x-1}\)
\(=\dfrac{x-2\sqrt{x}+1}{\left(x-1\right)}=\dfrac{\sqrt{x}-1}{\sqrt{x}+1}\)
b: Để P=-1 thì \(\sqrt{x}-1=-\sqrt{x}-1\)
=>x=0
c: \(P-1=\dfrac{\sqrt{x}-1-\sqrt{x}-1}{\sqrt{x}+1}=\dfrac{-2}{\sqrt{x}+1}< 0\)
=>P<1