a: \(M=\dfrac{x+1}{\sqrt{x}+1}\cdot\dfrac{x+\sqrt{x}+1-\sqrt{x}-2}{x+\sqrt{x}+1}\)
\(=\dfrac{\left(x+1\right)\left(\sqrt{x}-1\right)}{x+\sqrt{x}+1}\)
b: Khi \(x=\left(3-2\sqrt{2}\right)^2\) thì \(M=\dfrac{\left(17-12\sqrt{2}+1\right)\left(3-2\sqrt{2}-1\right)}{17-12\sqrt{2}+3-2\sqrt{2}+1}\)
\(=\dfrac{\left(18-12\sqrt{2}\right)\left(2-2\sqrt{2}\right)}{21-14\sqrt{2}}\)