TeX source:
\begin{array}{rclcl}\mathbb{D} &=& \mathbb{R} \cr \cr 7 \cdot e^{15x^2-30x} &=& 21 &\vert& :7 \cr e^{15x^2-30x} &=& 3 &\vert& \ln() \cr 15x^2-30x &=& \ln(3) &\vert& :15 \cr x^2-2x &=& \dfrac{\ln(3)}{15} &\vert& - \dfrac{\ln(3)}{15} \cr x^2-2x-\dfrac{\ln(3)}{15} &=& 0 &\vert&\text{p-q-Formel} \cr x_{1,2} &=& 1\pm\sqrt{1+\dfrac{\ln(3)}{15}} \cr\cr x_1 &=& 1+\sqrt{1+\dfrac{\ln(3)}{15}} \approx 2{,}04 \cr x_2 &=& 1-\sqrt{1+\dfrac{\ln(3)}{15}} \approx -0{,}04 \cr \cr \mathbb{L} &=& \left\{1+\sqrt{1+\dfrac{\ln(3)}{15}};\,1-\sqrt{1+\dfrac{\ln(3)}{15}}\right\}\end{array}