$$ \begin{aligned} 2\text{e}^{2-x}-\text{e}^x &= 0\quad|\quad\cdot\text{e}^x\\\,\\ 2\text{e}^2-\left(\text{e}^x\right)^2 &= 0\\\,\\ 2\text{e}^2 &= \left(\text{e}^x\right)^2 \\\,\\ \sqrt{2}\cdot\text{e} &= \text{e}^x \\\,\\ x &= \frac { 2 + \sqrt{2} }{ 2 }. \end{aligned} $$