Respuesta :

From the definition of logarithm, we know that:

[tex]$a^y=b\quad\iff\quad y=\log_ab\qquad\quad \,\text{when }a,b\ \textgreater \ 0\,\,\text{ and }\,\,a\neq1[/tex]

In this case [tex]a=4[/tex] and [tex]b=5[/tex] so:

[tex]$\boxed{y=\log_45}[/tex]