I want to think that you are not an internet troll. This kind of ignorance point to an otherwise conclusion.
Do you know how the set $(3,6)$ is even defined?
Do you know what union means?
Do you have any idea what any of this is about?
If not, then you are a troll. Please prove us wrong.
Im not trolling anyone here. I understand that A = [-3, 8) and B = (6, 8]
Im wondering since the notation () and  are being used does this mean the set
A contains -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7
B contains 7, 8
so A u B is = 7?
is this correct?
or does A just contain [-3, 8) -3 and 8 and B (6, 8] just 6 and 8?
so A u B is = (-3, 6, 8)?
So you want the union of A = the set of all real numbers between -3 and 8, including -3 but not 8, and B = the set of all real numbers between 6 and 8, including 8 but not 6.
The union is (by definition) the set of all real numbers in either A or B.
Now is it easier to see the solution?