I don't understand how start solving it and i am confuse on what formula to use

Question

9. A certain forest covers an area of 1700km2 . Suppose that each year this area decreases by 5% . What will the area be after 6 years? Round your answer to the nearest square kilometer

Answer 1

A growth or decay by a fixed percent every year is an exponential function:

y = a·(1 + rate)^x

where y is the area of forest at year x, x is years, and a is the initial area of the forest = 1700 km². The rate is the percent increase of decrease each year, expressed in decimal form. Increases are +, decreases are -. In this problem, the area is decreasing at 5% per year, so rate = - 0.05. For x = 6 years:

y = 1700·(1 - 0.05)⁶

Use your calculator to compute the answer.