题目

Who might Allie be? A . The speakers' pet. B . The speakers' child. C . The neighbor's turkey. 答案:B17.已知全集U=R,A={x|x≥3},B={x|x2-8x+7≤0},C={x|x≥a-1}(1)求A∩B,A∪B;(2)若A∩C=C,求实数a的取值范围.
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