Allison's middle school team has designed t-shirts containing their team name and color. Allison and her friend Nicole have volunteered to call local stores to get an estimate on the total cost of purchasing t-shirts. Print-o-Rama charges a set-up fee, as well as a fixed amount for each shirt ordered. The total cost is shown below for the given number of shirts. Value T's and More charges $8 per shirt. Which company should they use? Questions on next slide.

The equation of a line is Y=mx+b
You know that the slope is -2 and the slope is 'm' so sub it into the equation.
Y=-2x+b
To have an equation of a line you need the 'b' or 'y' intercept and the slope.
This means you have to find the 'b' because you already know the slope which is -2. To find the 'b' you have to sub in the coordinates and then solve for 'b'
Y=-2x+b
(x,y)
(3,0)
0=-2(3)+b
0=-6+b
6=b
Therefore the equation of the line is Y=-2x+6