What's #log_5(125)#?

1 Answer

#x=12#

Explanation:

Let's first see that we can write #log_5(125)# as a number. It might be easier to see it if we use this rule:

#a^b=c <=> log_ac=b#

and so

#5^b=125#

The number it will become is the #b#. It turns out that #5^3=125# and so #b=3# and that is what the log will return:

#log_5(125)=3=x/4#

And now we can solve:

#x=12#