l o g 5 25 5 {\displaystyle log_{\sqrt {5}}{\frac {25}{\sqrt {5}}}}
l o g 5 5 2 5 {\displaystyle log_{\sqrt {5}}{\frac {5^{2}}{\sqrt {5}}}}
l o g 5 5 4 5 {\displaystyle log_{\sqrt {5}}{\frac {{\sqrt {5}}^{4}}{\sqrt {5}}}}
l o g 5 5 3 {\displaystyle log_{\sqrt {5}}{\sqrt {5}}^{3}}
a b = x ⇔ log a ( x ) = b {\displaystyle {\displaystyle a^{b}=x\Leftrightarrow \log _{a}(x)=b}}
5 x = 5 3 {\displaystyle {\sqrt {5}}^{x}={\sqrt {5}}^{3}}
x = 3 {\displaystyle x=3}