A simple technique that biologists use to estimate the age of an African elephant is to measure the length of the elephant's footprint and then calculate its age using the equation,

l= 45 - 25.7e ^-0.09a

where k is the length of the footprint and a is the age (in years).

a) Use the equation to find the ages of the elephants whose footprints are given.

1)36cm

2)32cm

3)28cm

4)24cm

b)Solve the equation for a, and use this equation to find the ages of the elephants whose footprints are given.

c) Compare the methods you used in parts (a) and (b). Which method do you prefer? Explain?