I'm terrible at logarithms ^^;;

I'd really like some help learning how to solve these kinds of equations:

8^x=4

9^x=27

I also dont get how to write logarithmic expressions as single logarithms when a problem like: log (x-1)^2-log (3x/4)^2. I dont understand what to do with the square...

I have the same problem with expanding equations with squares in them like: log base of 2 (x + 1)^2

log base of 4 r^2 t

Help would be much appreciated :]