Do not solve or want solution Domain question what can not b

Do not solve or want solution. Domain question, what can not be the domain? It is the opposite of what we can use.

Domain of LHS : loga(x^2 +4)

x^2 +4 is always >0

So,check for loga(4x -7)

4x -7>0 ; x > 7/4

So, for values less than 7/4 i.e. x< = 7/4 there are no solution

So, ( -inf , 7/4] is not the domain