3-x |
x2+1 |
1 |
a |
1 |
a |
1 |
a |
1 |
a |
1 |
a |
1 |
a |
1 |
a |
1 |
a |
1 |
a |
1 |
2 |
1 |
2 |
A.Æ | B.{x|x≥1} | C.{x|x≥4} | D.{x|x≥1或x≤-1} |
A.{a|1≤a≤9} | B.{a|6≤a≤9} | C.{a|a≤9} | D.∅ |
A.、{-2,1} | B..{1,2} | C.{-1,-2} | D..{-1,2} |
A.{2,4,6} | B.{1,3,5} | C.{2,4,5} | D.{2,5} |
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