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put this solution on YOUR website!Increasing means the slope is positive. Decreasing means the slope is negative. You can identify this easily via the graph. To do it without a graph you really need calculus for full effect.
So, let's look at the graph of f(x)=x^2-x-2:
We can see right away that the function is decreasing until x=1/2 (which is the vertex). After x=1/2 the function is increasing.
In interval notation we will say: D: (-infinity,1/2) I: (1/2,infinity). Furthermore, we can accurately describe x=1/2 as the minimum of the function due to the behavior around x=1/2.