I would have to assume that the correct form of the formula is:
 f(x) = 14,600(1.1)^x
 where x is time in years and is an exponent of (1.1)
 Since we are finding for the original population, therefore x = 0
 f(x) = 14,600 (1.1)^0
 Any number raised to the power of 0 is just equal to 1. Therefore:
 f(x) = 14,600
 The original population is 14,600.