Đáp án đúng: D
Giải chi tiết:\(\begin{array}{l}\left| {x - 12} \right| - 18 = {3^2} - {2^3}{.2020^0}\\\left| {x - 12} \right| - 18 = 9 - 8.1\\\left| {x - 12} \right| - 18 = 1\\\left| {x - 12} \right| = 18 + 1\\\left| {x - 12} \right| = 19\\TH1:\,\,\,\,x - 12 = 19\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\, = 12 + 19\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\, = 31\\TH2:\,\,\,\,x - 12 = - 19\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\, = \left( { - 19} \right) + 12\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\, = - 7\end{array}\)
Vậy \(x = 31\) hoặc \(x = - 7.\)
Chọn D.