Question

mn giúp e với ạ e đg cần gấp ạ

Answer 1

12: \(=\dfrac{\sqrt{x}+1-x+2\sqrt{x}+3}{x-1}:\dfrac{x+3+2\sqrt{x}-2}{x-1}\)

\(=\dfrac{-x+3\sqrt{x}+4}{x-1}\cdot\dfrac{x-1}{x+2\sqrt{x}+1}\)

\(=\dfrac{-\left(\sqrt{x}-4\right)\left(\sqrt{x}+1\right)}{\left(\sqrt{x}+1\right)^2}=\dfrac{-\sqrt{x}+4}{\sqrt{x}+1}\)

13: \(=\dfrac{2x+1-x-\sqrt{x}-1}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}:\dfrac{x+\sqrt{x}+1-x-4}{x+\sqrt{x}+1}\)

\(=\dfrac{x-\sqrt{x}}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\cdot\dfrac{x+\sqrt{x}+1}{\sqrt{x}-3}\)

\(=\dfrac{\sqrt{x}}{\sqrt{x}-3}\)