I just cannot get this one. I think I have to do something with log but that's as far as I can go.
5^x=100
log ( a ^ n ) = n log ( a )
x log ( 5 ) = log ( 100 ) Divide both sides by log ( 5 )
x = log ( 100 ) / log ( 5 )
x = 2.8613531
5 ^ 2.8613531 = 100