Error)
2)A={x|x=t? -2t-3 & gt; =-4},B={y|y=2x? -8x+4 & gt; =-4},
So A∩B=A∪B=[-4,+∞).
3) This question is given a number. Just list the intersection and union of each term, without your theoretical proof.
I don't know which one is better online, but I'd better recommend some books to you.
One lesson and one practice, reading and doing problems, the five-star question bank published by China Normal University, which was relied on by high schools in those days, I hope it will help you.