In two or more complete sentences, explain how to find the interval(s) in which the function f(x) is decreasing and how interval notation is used to express the interval(s). in your final answer, include the interval in which the function is decreasing.

The function is increasing when the slope is greater than zero and decreasing when the slope is less than zero.  Slope is (y2-y1)/(x2-x1) or the change in y divided by the change in x.

In this case the function is decreasing when x=[-8,-5) and when x=[4,8)

So in interval notation:  x=[-8,-5)U[4,8)