When you want to solve fastly, you can use the method of changing to same base.
(2^4)^x=64
(16)^x=64
(16)^x=(16)^(3/2)
x=3/2
Use base 2 is easier than base 16
2^(4x)=64
2^(4x)=2^(6)
(4x)=(6)
x=6/4
x=3/2
Standard solve I use logarithmic (for such as not same base)
2^(4x)=64
log(2^(4x)) = log(64)
4x*log(2) = log(64)
4x*log(2) = log(2^6)
4x*log(2) = 6*log(2)
4x=6
x=6/4
x=3/2
Not sure about your presentaion. Is it :-
Question 1
(2^4) (x) = 64
16 x = 64
x = 4
or
Question 2
2^(4x) = 64
4x log 2 = log 64
4x = log 64 / log 2 (logs to base 2)
4x = 6
x = 3/2