Question 46500
<b>Please show me how to  evaluate this without using a calculator?

log5 20 . log20 60. log60 100 . log100 125.

Thanks!</b>

In general, log[a]b * log[b]c = log[a]c

So, log[5]20 * log[20]60 = log[5]60
Then, log[5]60 * log[60]100 = log[5]100
And, log[5]100 * log[100]125 = log[5]125

Finally, log[5]125 is the number you have to raise 5 to in order to get 125. That number is {{{highlight(3)}}}.