The equation y = 80x represents the relationship between the number of miles traveled (y) and the number of hours traveled (x) by Isaiah from Nashville to Atlanta. Since the equation is a linear equation in slope-intercept form, we can see that the rate of change is constant at 80 miles per hour.
To graph the relationship between the two scenarios, we can plot the points on a coordinate grid. Jason's journey can be represented by the point (2, 180) and Isaiah's journey can be represented by the line y = 80x.
Since Isaiah's rate of change is greater than Jason's, we can see that the line y = 80x has a steeper slope than the line representing Jason's journey. Therefore, the graph of the relationship with the greater rate of change is the line y = 80x.