The question gives you the formula to use, but it's printed wrong.
The 'x' is an exponent after the (1 + r).
All you have to do is take the formula, and write the numbers into it
that are also given.
The key thing to spot is that the forest is decreasing, so the 'r' is negative,
just as if you had money in a savings account and every year the bank took
6% out of it.
So the formula to use is f(x) = P (1 + r) ^x
P = 2000
r = -0.06
f(x) = 2000 (1 - 0.06)^x
= 2000 (0.94)^x
The amount left after 12 years is
2000 (0.94)¹² =
2000 (0.476) = 951.8 square kilometers.
