Question

rút gọn

\(B=\dfrac{x-3\sqrt{x}+4}{x-22}-\dfrac{1}{\sqrt{x}-2}\left(x>0,x\ne4\right)\)

Answer 1

Sửa đề: \(B=\dfrac{x-3\sqrt{x}+4}{x-2}-\dfrac{1}{\sqrt{x}-2}\)

Ta có: \(B=\dfrac{x-3\sqrt{x}+4}{x-2}-\dfrac{1}{\sqrt{x}-2}\)

\(=\dfrac{x-3\sqrt{x}+4}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}-\dfrac{\sqrt{x}+2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}\)

\(=\dfrac{x-3\sqrt{x}+4-\sqrt{x}-2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}\)

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