Y intercept: when x = 0
Coordinate will be (0, y)
Look at the graph
Solution: y intercept: (0, 140)
Slope is the rate of change
(20,100) (0,140)
Slope formula: (y2-y1)/(x2-x1)
(140-100)/(0-20) = 40/-20 = -2
Solution: the slope is -2
Now use formula: f(x) = mx + b
m = slope, b = y intercept
Solution: function: f(x) = -2x + 140
