ĐK: x>/0
\(\dfrac{\sqrt{x}-1}{\sqrt{x}+1}< \dfrac{2}{3}\Leftrightarrow\dfrac{3\left(x-1\right)}{3\left(x+1\right)^2}< \dfrac{2\left(x+1\right)^2}{3\left(x+1\right)^2}\) (1)
Vì 3(x+1)^2 >0
(1) \(\Leftrightarrow3x-3< 2x^2+4x+2\Leftrightarrow2x^2+x+5>0\Leftrightarrow x\in R\)
Kl: x >/ 0