Don't get any of this

Part a- represent V as a function of t

step 1: find the slope by picking any two coordinates and using the slope formula
m=(y2-y1)/(x2-x1)

-i chose (8,2000) and (4,7000) but it doesn't matter what you choose.

-plug in:
m=(7000-2000)/(4-8)=-5000/4=-1250

step 2: plug any coordinate into equation y=mx+b

- i chose (0,12000)

- plug in:
(12000)=(-1250)(0)+b

- solve for b
b=12000

step 3: V as a function of t
- use slope intercept equation y=mx+b
- V(t)=y
- t=x
- m=-1250
- b=12000
V(t)=-1250t+12000 (final answer)

part b- graph it

part c- the slope represents the rate at which the copier decreases in value over t years.