Răspuns :
[tex]8^{x}=4^{2x+1}\\
\\ (2^{3})^{x}=(2^{2})^{2x+1}\\
\\ 2^{3x}=2^{2(2x+1)}\\
\\ 2^{3x}=2^{4x+2}\\
\\ \Rightarrow 3x=4x+2\\
\\ -2=4x-3x\\
\\ \boxed{x=-2},~S=\{-2\}[/tex]
\\ (2^{3})^{x}=(2^{2})^{2x+1}\\
\\ 2^{3x}=2^{2(2x+1)}\\
\\ 2^{3x}=2^{4x+2}\\
\\ \Rightarrow 3x=4x+2\\
\\ -2=4x-3x\\
\\ \boxed{x=-2},~S=\{-2\}[/tex]