posted by Penny .
A boat is worth $7,000 when it is 5 years old and $2,000 when it is 10 years old. What is the slope intercept equation?
You have two points: (5,7000) and (10,2000)
the two-point equation for the line is thus
(y-7000)/(x-5) = (2000-7000)/(10-5)
or, after rearranging things a bit:
y = -1000x + 12000
That is, the value started at $12,000, and depreciates $1000/year