1: Thay x=9 vào A, ta được:
\(A=\dfrac{3+1}{3+2}=\dfrac{4}{5}\)
2: Ta có: \(B=\dfrac{\sqrt{x}-11}{x-\sqrt{x}-2}-\dfrac{\sqrt{x}}{\sqrt{x}+1}+\dfrac{2\sqrt{x}-1}{\sqrt{x}-2}\)
\(=\dfrac{\sqrt{x}-11-x+2\sqrt{x}+2x+2\sqrt{x}-\sqrt{x}-1}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\)
\(=\dfrac{x+4\sqrt{x}-12}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\)
\(=\dfrac{\sqrt{x}+6}{\sqrt{x}+1}\)
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