The function:
f ( x ) = x * 0.965^t
where x is the initial amount and t is the number of the years
80 = x * 0.965^3
80 = x * 0.89632
x = 80 : 0.89632 ≈ 89
Answer:
The initial amount of animals was 89.
Eight hundred seven million, five hundred thirty thousand, twelve
f(x) = x² - 8x + 5 Plug in -1 for all of the x-values
f(-1) = (-1)² - 8 (-1) + 5 Square -1
f(-1) = 1 - 8 (-1) + 5 Multiply -8 and -1
f(-1) = 1 + 8 + 5 Add
f(-1) = 14