Answer :
Use the log definition:
[tex]log_28=x \rightarrow 2^x=8\\ \\ 2^x=2^3 \rightarrow \boxed{x=3}[/tex]
[tex]log_28=x \rightarrow 2^x=8\\ \\ 2^x=2^3 \rightarrow \boxed{x=3}[/tex]