đk: $x \neq 0$đặt $t = 3^{|x|}\Rightarrow pt(1) \Leftrightarrow t^{2} - 4t + 3 < 0$$\Leftrightarrow \begin{cases}0 < x < 1 \\ -1 < x < 0 \end{cases}$$pt(2)\Leftrightarrow 1 > \frac{1}{2^{\frac{2}{x}+x+2}}$$\Leftrightarrow 2^{\frac{2}{x}+x+2} > 1$$\frac{2}{x}+x+2 > 0 \forall x\in R$$\setminus 0$KL: $\begin{cases}0 < x < 1 \\ -1 < x < 0 \end{cases}$
đk: $x \neq 0$đặt $t = 3^{|x|}\Rightarrow pt(1) \Leftrightarrow t^{2} - 4t + 3 < 0$$\Leftrightarrow 0 < x < 1 hoặc -1 < x < 0 $$pt(2)\Leftrightarrow 1 > \frac{1}{2^{\frac{2}{x}+x+2}}$$\Leftrightarrow 2^{\frac{2}{x}+x+2} > 1$$\frac{2}{x}+x+2 > 0 \forall x\in R$$\setminus 0$KL: $0 < x < 1 hoặc -1 < x < 0 $