the value, v, of a shopkeeper's inventory software program is given by v=-1/2t+3.

Where t is the number of years since the shopkeeper bought the program. What is the program worth 6 years after it is first purchased?

Plot the point with the given t-value, 6.

to get this, you just substitute t=6 to the given equation:

v = (-1/2)t + 3
v = (-1/2)*6 + 3
v = -3 + 3
v = 0

plot:
h t t p : / / w w w 4 c . w o l f r a m a l p h a . c o m / Calculate/MSP/MSP412219fd25cdf0efbh880000587daeb9i9ea74bg?MSPStoreType=image/gif&s=11&w=424&h=166&cdf=Coordinates&cdf=Tooltips

..without the spaces~