Resposta :
[tex] 3^{2x}-28.3^x+27=0 \\
(3^x)^2-28.3^x+27=0 \\
\boxed{y=3^x} \\
y^2-28y+27=0 \\
y_1=1 \\
y_2=27 \\
\boxed{3^x=1 \rightarrow x=0} \\
\\
\boxed{3^x=27 \rightarrow x=3}
[/tex]
S=(0,3}
S=(0,3}