Bài 1:
Đặt [tex]h=\frac{x}{x+1} (x\in (-\infty ;1)\cup(0;+\infty ))[/tex]
Ta có: [tex]h-2\frac{1}{\sqrt{h}}-3=0\Leftrightarrow \frac{(\sqrt{h})^3-2-3\sqrt{h}}{\sqrt{h}}=0\Rightarrow (\sqrt{h})^3-3\sqrt{h}-2=0\Rightarrow \sqrt{h}=2\Rightarrow h=4\Rightarrow \frac{x}{x+1}=4\Rightarrow x=\frac{-4}{3}[/tex]