Question

Giúp Vy luôn mấy bài này nhé

Answer 1

Bài 3: a, tại x=\(\frac{16}{9}\)=> A=\(\frac{\sqrt{\frac{16}{9}}+1}{\sqrt{\frac{16}{9}}-1}=\frac{\frac{4}{3}+1}{\frac{4}{3}-1}=\frac{\frac{7}{3}}{\frac{1}{3}}=7\)

tại x=\(\frac{25}{9}\Rightarrow A=\frac{\sqrt{\frac{25}{9}}+1}{\sqrt{\frac{25}{9}}-1}=\frac{\frac{5}{3}+1}{\frac{5}{3}-1}=\frac{\frac{8}{3}}{\frac{2}{3}}=4\)

b, Ta có : \(\frac{\sqrt{x}+1}{\sqrt{x}-1}=\frac{\sqrt{x}-1+2}{\sqrt{x}-1}=1+\frac{2}{\sqrt{x}-1}=5\)

\(\Rightarrow\frac{2}{\sqrt{x}-1}=5-1=4\)

=> \(4.\left(\sqrt{x}-1\right)=2\\ \Rightarrow\sqrt{x}-1=\frac{1}{2}\\ \)

\(\Rightarrow\sqrt{x}=\frac{1}{2}+1\\ \Rightarrow\sqrt{x}=\frac{3}{2}\\ \Rightarrow x=\sqrt{\frac{3}{2}}\)