Changing from log form to equivalent exponent form we get:
4^x = 32
Then changing to prime bases on each side we get
(2^2)^x = 2^5 which is the same as 2^(2x) = 2^5
Now since the bases are (cooperatively) the same on each
side, the exponents must be the same: i.e. 2x = 5
or x = 5/2
[Were the prime bases NOT the same on each side then you would "force" the same base, e or 10 on each side -- and you'd probably require a calculator.]