Đáp án:
$\left[\begin{array}{l}x =12\\x =8 \end{array}\right.$
Giải thích các bước giải:
$\begin{array}{l}\quad 10^{2020}\vert x - 10\vert = 20.10^{2019}\\ \Leftrightarrow 10^{2020}\vert x - 10\vert = 2.10.10^{2019}\\ \Leftrightarrow 10^{2020}\vert x - 10\vert = 2.10^{2020}\\ \Leftrightarrow \vert x-10\vert = 2\\ \Leftrightarrow \left[\begin{array}{l}x - 10 = 2\\x - 10 = -2 \end{array}\right.\\ \Leftrightarrow \left[\begin{array}{l}x =12\\x =8 \end{array}\right.\\ \end{array}$