The exponential decay graph shows the expected depreciation for a new boat, selling for $3500, over 10 years a. write an exponential function for the graph.
b. use the function in part a to find the value of the boat after 9.5 years.

For the answer to the question above,  
V(n) = a * b^n, where V(n) shows the value of boat after n years. 
V(0) = 3500 
V(2) = 2000 

n = 0 
V(0) = a * b^0 = 3500 
a = 3500 

V(2) = a * b^2 
2000 = 3500 * b^2 
b = sqrt (2000/3500) 
b ≈ 0.76 

V(n) = 3500 * 0.76^n 

We can check it for n = 1 which is close to 2500 in the graph: 
V(1) = 3500 * (0.76)^1 
V(1) = 2660 

And in the graph we have V(3) ≈ 1500, 
V(n) = 3500 * (0.76)^3 ≈ 1536 

Now n = 9.5 
V(9.5) = 3500 * (0.76)^(9.5) 
V(9.5) ≈ 258