b: \(N=\dfrac{2x-5\sqrt{x}+2}{x-2\sqrt{x}}-\dfrac{\sqrt{x}+1}{\sqrt{x}}\)
\(=\dfrac{\left(\sqrt{x}-2\right)\left(2\sqrt{x}-1\right)}{x-2\sqrt{x}}-\dfrac{\sqrt{x}+1}{\sqrt{x}}\)
\(=\dfrac{2\sqrt{x}-1-\sqrt{x}-1}{\sqrt{x}}=\dfrac{\sqrt{x}-2}{\sqrt{x}}\)