Answer:

Explanation:
Mr Samuel Planted 40 pepper plants in 2005.
Therefore:
f(0)=40
Each year the number of pepper plants doubled.
In 2006, f(1)=40*2
In 2007, f(2)=40*2*2

In 2008, f(3)=40*2*2*2

If we continue in like manner. The number of pepper plants after x years will be given by the exponential function:

where 40 is the initial number and 2 is the growth factor.