If you evaluate f in x=0, you obtain that f(0) = 185*1.2⁰ = 185*1 = 185. This means that after 0 years, the number of foxes on the reservation is 185. In other words, the reservation starts with 185 years and then it grows. 185 here represents, as a result, the value of f, in other words the number of foxes, at time t=0.
