Đáp án đúng: D
Giải chi tiết:\(\begin{array}{l}{3^x} + 25 = {26.2^2} + {2.3^0}\\\,\,\,\,\,\,\,{3^x} + 25 = 26.4 + 2.1\\\,\,\,\,\,\,\,{3^x} + 25 = 104 + 2\\\,\,\,\,\,\,\,{3^x}\,\,\,\,\,\,\,\,\,\,\,\,\, = 106 - 25\\\,\,\,\,\,\,{3^x}\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 81\\\,\,\,\,\,\,{3^x}\,\,\,\,\,\,\,\,\,\,\,\,\,\, = {3^4}\\\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 4.\end{array}\)
Vậy \(x = 4.\)
Chọn D.