Question

Giúp mình với

Answer 1

a: Khi x=9 thì \(A=\dfrac{1-3}{1+3}=\dfrac{-2}{4}=-\dfrac{1}{2}\)

b: \(B=\dfrac{-\sqrt{x}-15+2\sqrt{x}-10}{x-25}\cdot\dfrac{\sqrt{x}-5}{\sqrt{x}+1}\)

\(=\dfrac{\sqrt{x}-25}{\sqrt{x}+5}\cdot\dfrac{1}{\sqrt{x}+1}\)