Can somebody please answer my two unanswered questions from before? Thank you! New question!

Find a/b when 2log(a-2b)=log a + log b.

We have

2log (a - 2b)   =  log (a * b)

log (a - 2b)^2  = log (a * b)

Then......this implies that

(a - 2b)^2  = ab

a^2 - 4ab + 4b^2  =  ab

a^2 - 5ab + 4b^2 = 0

Factor

(a - 4b) (a - b)  = 0

The....setting both factors to 0 and solving

a =  4b  →  a/b  = 4

And 

a = b

a/b = 1

The first solution is good whenever a > 0

The second solution is good whenever a < 0