The rate of change is (-1)
To solve this, we need to look at graphic to know the values of the function f(x) when x is equal to 1 and 3.
Then we have two points of the graph: (1,6) and (3,4).
The rate of change between two points is:
[tex]m=\frac{\text{change in f(x)}}{change\text{ in x}}[/tex]In this case,
[tex]m=\frac{4-6}{3-1}=\frac{-2}{2}=-1[/tex]Note that its the same whatever coordinate put first:
[tex]\frac{6-4}{1-3}=\frac{4-6}{3-1}=-1[/tex]But when you do the difference between the coordinates, make sure to respect the order: if you use the y coordinate of the point P minus the y coordinate of point Q, you must to do the same for the x coodinate; Px-Qx
