设全集为U=R,集合A为函数f(x)=
x+1+lg(3−x)−1的定义域,B={x|2x-4≥x-2}
(1)求A∪B,∁U(A∩B)
(2)若集合C={x|2x+a>0},满足B∪C=C,求实数a的取值范围.