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设A={-2≤x ≤a,0
人气:299 ℃ 时间:2020-01-28 21:47:47
解答
-2<=x<=a
0所以0²<=x²<=2²
所以C={z|0<=z<=4}
-2<=x<=a
-1<=2x+3<=2a+3
B={y|-1<=y<=2a+3}
C⊆B
所以2a+3>=4
所以a>=1/2
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