The DePeppo children, Ann, Debbie, Damian, and Adam created a contest to test their

(0,18500)

(1,17390), (1,17500)

(2,16346.60), (2,16500)

(3,15365.80), (3,15500)

a.)

  (17390-16346.60)/(1-2)

-$1013.40

18500(a)^1=17390

17390/18500=a

a=0.94

(16346.60-15365.80)/(2-3)

-$980.80

18500(a)^2=16346.60

16346.60/18500=a^2

0.8836=a^2

a=0.94

car 1 is decreasing at a variable negative linear slope, but at a constant exponential rate of 0.94

(17500-16500)/(1-2)

-$1000

(16500-15500)/(2-3)

-$1000

car 2 is decreasing at a constant negative linear slope of 1000 annually

b.) car 1=f(x)=18500(0.94)^x

car 2=f(x)=18500-1000x

c.) car 1 would have the greatest value after nine years, at $10600.40, as it's value is decreasing by 6% annually while car 2's value is decreasing at $1000 annually. the difference in value between the two cars after nine years is around $1100, which is fairly significant. 

f1(9)=18500(0.94)^(9)

f1(9)=$10600.40

f2(9)=18500-1000(9)

f2(9)=$9500