(12^-x)=2.092....x=? 16^(log x / log 2)=1.43...x=?

[Participant]

Hello

I'm trying to solve x for the above two equations. Can someone please give me a general rule as to how to do that? Totally forgotten my Pure Maths from A-Level! I'm semi-sure with the power of -x, there's a log involved, but I just can't remember the construction.

Thanks!