Sorry, by second do you mean bottom right? Assuming that it is. No. I do not negate anything, I only do two things, union or intersect. Since in the second one (bottom left) you have already shaded notA intersect B, and more importantly because you are asked to UNION with notC, you just SHADE MORE, with no regard for what was shaded before, it is still shaded and so is notC.
Watch the video again, and try to get the concept, then you should be able to apply that to yours, this is important in math, it is not about each case, but being able to do ALL cases. Anyways, sorry for the teacher speech! 1. That bracket tells you to shade (Inside A AND Inside B), so the cat's eye, or the overlap. Shade that first and bracket is done. 2. Then the union of C' is just ALSO shading everything outside of C. Don't erase anything you had before. If you have overlap, it doesn't matter, it is still shaded and that is what matters. Are you good with the idea that C' and C with a bar over both mean C not? That is key. Watch example #1 again, it is very similar, but you start with Inside both A AND B