As we see in the graph, initially, when x increases, y decreases. The graph goes downward.
The slope of the line segment from (0, 0) to (3, -3) is -1. Here's how it's calculated:
[tex]\begin{gathered} m=\frac{rise}{run} \\ \\ m=\frac{-3-0}{3-0} \\ \\ m=-1 \end{gathered}[/tex]
Next, from x =3 to x = 5, we see that the graph is going upward. So, y is increasing.
Again, to calculate the slope, we use m = rise/run.
[tex]\begin{gathered} m=\frac{3-(-3)}{5-3} \\ \\ m=\frac{6}{2} \\ \\ m=2 \end{gathered}[/tex]
So the slope of the line segment from (3, -3) to (5, 3) is 2.
For x between x = 0 andx = 4, the function value y goes downward (decreasing) then back to 0.
For x between x = 4 and x=8, the function value y goes upward (increasing) then back to 0.