A car purchased for $11900 has a resale value of $2000 after 10 years. Assuming its resale value decreased linearly over these years, what was the resale value of the car after 3 years?
two given ordered pairs:
(0,11900)
(10,2000)
m = slope = (2000-11900)/ (10 - 0) =-990 per year
so
11900 - 3(990) = 8930