Question 536833
When bought {{{t=0}}} {{{v=6}}} the value was 6.
Six years after the software was bought {{{t=6}}} and
{{{v=-(1/2)*t+6=-(1/2)*6+6=-3+6=3}}}
If you plot value versus time (in years) since the program was bought you will have something like this (pretend it's t instead of x for the horizontal axcis scale and v instead of y in the vertical axis):
{{{graph( 400, 200, -2, 14, -1, 7, 6-x/2 )}}}{{{v=-(1/2)*t+6}}}is the equation of a straight line that goes through y=6 (or v=6) as a value for the function when the independent variable is x=0 (or t=0). and goes down by 1/2 each time you go 1 unit to the right (one unit increase in x or t).