Logarithm

Solve the shown logarithm:

Hint
The logarithm of $$x$$ to the Base $$b$$ is defined by
$$$log_b(x)=c$$$
where $$b^c=x$$ .
Hint 2
Factor 25 from 15,625.
The logarithm of $$x$$ to the Base $$b$$ is defined by
$$$log_b(x)=c$$$
where $$b^c=x$$ .

The problem is asking to solve for $$c$$ :
$$$36^c=15,625$$$
Factor $$25$$ from $$15,625$$ :
$$$\frac{15,625}{25}=625\rightarrow \frac{625}{25}=25$$$
$$25$$ evenly appears three times in $$15,625$$ . Thus,
$$$log_{25}(25^3)=3$$$
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