log help

Look at log base 10      log 1000 = 3       10^(log1000) = 10^3 = 1000

now put in logbase 7    Log7  x =  y  

                                          which means   7^y  = x

                                                                       then  7^log7 x  = 7^y    which would equal  x

This uses the log property that says

a  ^{log _a b}     =   b

So 

7  ^{log ₇ x}   =   x