using the property of logarithms log(a)b = x => a^x = b so we get
(2x-4)^4 = 16
(2x-4)^4 = 2^4 because the exponents are equal so this equation will be right than the bases will be equals too so than
2x -4 = 2
2x = 6
x = 6/2 = 3
x = 3
hope this will help you