Resposta:
Olá bom dia!
[tex]3^x-28*3^x + 27 = 0\\\\3^x(1-28) + 27 = 0\\\\3^x(1-28) = -27\\\\3^x = -27/-27\\\\3^x = 1\\\\Como:\\\\n^0 = 1 \ para \ todo \ n:\\\\x = 0\\\\S = {0}[/tex]
