(1)当a=3时,求A∪B;
(2)若A⊆B,求实数a的取值范围.
(Ⅰ)若集合M是单元素集,求实数a,b满足的关系式;
(Ⅱ)若1,3∈M,求实数a,b的值.
(Ⅰ)若m=1,求A∪B;
(Ⅱ)若A∩B=A,求实数m的取值范围.