Bài 4:
a: \(B=\dfrac{x-1}{\sqrt{x}}:\dfrac{x-1+1-\sqrt{x}}{x+\sqrt{x}}\)
\(=\dfrac{x-1}{\sqrt{x}}\cdot\dfrac{\sqrt{x}\left(\sqrt{x}+1\right)}{\sqrt{x}\left(\sqrt{x}-1\right)}=\dfrac{\left(\sqrt{x}+1\right)^2}{\sqrt{x}}\)
b: Khi x=3-2 căn 2 thì \(B=\dfrac{\left(\sqrt{2}-1+1\right)^2}{\sqrt{2}-1}=\dfrac{2}{\sqrt{2}-1}=2\sqrt{2}+2\)