x | f(x)
25 | 2
125 | 3
625 | 4
From my research, the above table belongs to the question. The values in x show increasing exponential values of 5, where:
5^2 = 25
5^3 = 125
5^4 = 625
As for the case of f(x), they are the values of the powers. So the logarithmic function that would explain the values of x and f(x) would be:
A base-5 function:
f(x) = log5 x