decreaseing means where it is going down
those blank points mean not including
brackets mean inlclude, it's like the ≤ or ≥ sign
parenthasees means not include, it's like the < or > sign
it is going down from -8 to -5, not including -5 so [-8,-5)
also going down from 4 to 8, not including 8, so [4,8)
the union is including both
[-8,-5) U [4,8) is answer for where the function is decreasing
