TeX source:
\begin{array}{rclcl} u_1 = 10^{x_1} &=& 5 &\vert& \lg() \cr x_1 &=& \lg(5) \approx 0{,}70 \cr\cr u_2 = 10^{x_2} &=& 3 &\vert& \lg() \cr x_2 &=& \lg(3) \approx 0{,}48 \cr\cr\mathbb{L}&=&\left\{\lg(3); \lg(5) \right\}\end{array}