Bài 1:
a: Thay x=25 vào A, ta được:
\(A=\frac{\sqrt{25}+2}{\sqrt{25}-2}=\frac{5+2}{5-2}=\frac73\)
b: \(B=\frac{\sqrt{x}-1}{\sqrt{x}}-\frac{1}{\sqrt{x}+1}+\frac{3\sqrt{x}+1}{x+\sqrt{x}}\)
\(=\frac{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)-\sqrt{x}+3\sqrt{x}+1}{\left(\sqrt{x}+1\right)\cdot\sqrt{x}}=\frac{x-1+2\sqrt{x}+1}{\sqrt{x}\left(\sqrt{x}+1\right)}\)
\(=\frac{x+2\sqrt{x}}{\sqrt{x}\left(\sqrt{x}+1\right)}=\frac{\sqrt{x}\left(\sqrt{x}+2\right)}{\sqrt{x}\left(\sqrt{x}+1\right)}=\frac{\sqrt{x}+2}{\sqrt{x}+1}\)
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