math
posted by sophia on .
The value of a car decreases at a constant rate as it grows older. When the car is 2 years old, it is worth $23,000. When the car is 5 years old it is worth $15,500.
Write and equation relating y (value of the car $) to x (age of car).
Is it y23,000=2500(2)5 ??

so you are looking for a linear relation in the form y = mx + b
where you are given two points
(2,23000) and (5,15500)
so slope = (1550023000)/(52)= 7500/3
= 2500
so y = 2500x + b
sub in the first point
23000 = 2500(2) + b
b = 28000
finally :
y = 2500x + 28000 
how did you get b= 28000