a: \(P=\dfrac{\left(\sqrt{x}-2\right)\left(x-1\right)}{x\sqrt{x}-2x+2x-4\sqrt{x}+\sqrt{x}-2}+\dfrac{\left(\sqrt{x}+2\right)\left(x-1\right)}{x\sqrt{x}+2x-2x-4\sqrt{x}+\sqrt{x}+2}\)
\(=\dfrac{x-1}{x+2\sqrt{x}+1}+\dfrac{x-1}{x-2\sqrt{x}+1}\)
\(=\dfrac{\sqrt{x}-1}{\sqrt{x}+1}+\dfrac{\sqrt{x}+1}{\sqrt{x}-1}=\dfrac{2x+2}{x-1}\)
b: P=(2x-2+4)/(x-1)=2+4/(x-1)
P là số nguyên lớn nhất
=>x-1=1
=>x=2