Question

cho A=(1/căn x - 3 +1/ căn x+3) x (1-3/ căn x)

Answer 1

\(đkx>0;x\ne9\\ A=\left(\dfrac{\sqrt{x}+3+\sqrt{x}-3}{x-9}\right)\left(\dfrac{\sqrt{x}-3}{\sqrt{x}}\right)\\ A=\dfrac{2\sqrt{x}}{x-9}.\dfrac{\sqrt{x}-3}{\sqrt{x}}=\dfrac{2}{\left(\sqrt{x}+3\right)}\)

Answer 2

\(=\dfrac{\sqrt{x}+3+\sqrt{x}-3}{x-9}\cdot\dfrac{\sqrt{x}-3}{\sqrt{x}}\)

\(=\dfrac{2}{\sqrt{x}+3}\)