Since the temperature starts at 40 degrees F at sunrise and increases 4 degrees every hour afterward, we can begin our equation.
If you visualize the graph, the y-axis (left side) will denote the degrees and increase slightly every hour. The x-axis (at bottom) will show the hours as they pass by. In slope-intercept form, the b must be 40 degrees, since this is where we start, and the slope m must be 4, since this is the amount the temperature is changing every hour.
Therefore y=4x+40
This equation will tell you the temperature (y) at any hour (x).
