The slope of the graph is -0.5, and it shows that the velocity of the bus is -0.5 miles/min and is therefore slowing down.
How to measure the rate of change of something as some other value changes?
Suppose that we have to measure the rate of change of y as x changes, then we have:
[tex]Rate = \dfrac{y_2 - y_1}{x_2 - x_1}[/tex]
where we have
[tex]\rm when \: x=x_1, y = y_1\\when\: x = x_2, y= y_2[/tex]
Remember that, we divide by the change in independent variable so that we get some idea of how much the dependent quantity changes as we change the independent quantity by 1 unit.
(5 change per 3 unit can be rewritten as 5/3 change per 1 unit)
For a straight line, the slope of that line is the rate of increment of its output based on the input(the horizontal axis) usually.
Now, since in the considered graph, we have the x-axis as the axis for time measurement, and the y-axis as the axis for the distance measurement from home (by the bus):
Thus, we get:
Slope = Rate = [tex]\dfrac{\text{Difference in corresponding distance values}}{\text{Difference in time values}}[/tex] = velocity of the bus
Taking any two different time, at t = 2 seconds and at t = 4 seconds, we get the distance as 8 miles from home, and 7 miles from home respectively.
Thus, we get:
Velocity of the bus = [tex]\dfrac{7 - 8}{4 -2 } = -\dfrac{1}{2} = -0.5 \: \rm miles/min[/tex]
(there is difference between speed and velocity of an object)
The negative sign shows that the bus is slowing down. And as the time increases, the distance from home decreases, therefore, the bus is reaching to the home.
Learn more about average speed here:
https://brainly.com/question/12322912