a Let's first identify some points on the function.
Number of Stickers
x
Cost, y
1000
1
225
2000
2
225+80=305
3000
3
305+80=385
Each additional 1000 stickers cost $80. This tells us that the rate of change is constant and that this is a linear function. Let's recall the point-slope form of a linear function.
y-y_1= m(x-x_1)
Here m represents the slope of the line and (x_1,y_1) is a point on the line. Let's find the slope by substituting the points ( 1, 225) and ( 2, 305) into the Slope Formula.
The function has a slope of 80. We can now write an equation for the line by substituting 80 for m and the point ( 1, 225) for ( x_1, y_1) into the formula.
y- y_1&= m(x- x_1)
&⇓
y- 225&= 80(x- 1)
To get an equation that represents the total cost as a function of the number of stickers, we need to rewrite this into slope-intercept form.
