Jamie bought a car in 2005 for $28,500. By 2008 the car was worth $23,700. Based on a linear model, what will the value of the car be in 2012?

28500 - 23700 = 4800

2008 - 2005 = 3

so in 3 years, it went down 4800 ... that means it went down (4800/3) = 1600 per year

so in 2012 ... which is (2012 - 2005) = 7 years ... it would have gone down:

7 * 1600 = 11200

so the value of the car in 2012 is : (28500 - 11200) = 17,300 <==