Question

RÚT GỌN bt A=\(\left(\dfrac{\sqrt{x}+1}{x-9}-\dfrac{1}{\sqrt{x}+3}\right)\):\(\left(\sqrt{x}-3\right)\) với \(x\ge0;x\ne9\)

Answer 1

\(A=\left(\dfrac{\sqrt{x}+1}{x-9}-\dfrac{1}{\sqrt{x}+3}\right):\left(\sqrt{x}-3\right)\)

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

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