Đáp án đúng: C
Giải chi tiết:\(\begin{array}{l}123 - 5\left( {x + 4} \right) = 38\\\,\,\,\,\,\,\,\,\,\,\,\,5\left( {x + 4} \right) = 123 - 38\\\,\,\,\,\,\,\,\,\,\,\,\,5\left( {x + 4} \right) = 85\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x + 4 = 85:5\,\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x + 4 = 17\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\, = 17 - 4\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\, = 13\,\,\,\,\,\,\,\end{array}\)
Vậy \(x = 13\)
Chọn C.