Laws of Logarithms

Evaluate: without using a calculator, except for the first one. The 5.6 is supposed to be subscript, but i don't know how to make it small.

4log(5.6)84

log84/log5.6

Do I multiply this by four or something? both of the logs?

2 answers

One major rule of logs, used when changing bases is

log ba
= log a / log b

so 4 log 5.684
= 4(log 84 / log 5.6)
= 4(1.924279.../.74818..) = 10.2877
Thanks very much Reiny :)