答案:C
6.若{a,0,1}={c"," 1/b ",-" 1},则a= ,b= ,c= .
解析:∵-1∈{a,0,1},∴a=-1;
又0∈{c"," 1/b ",-" 1},∴c=0;由1/b=1得b=1.综上知,a=-1,b=1,c=0.
答案:-1 1 0
7.已知集合A={-1,3,2m-1},集合B={3,m2}.若B⊆A,则实数m= .
解析:∵B⊆A,且m2不可能取-1,∴m2=2m-1,解得m=1,经验证符合题意.
答案:1
8.已知集合P={1,2,3,4},Q={0,2,4,5},则满足A⊆P,且A⊆Q的集合A为 .
解析:若A=⌀,则满足A⊆P,且A⊆Q;
若A≠⌀,由A⊆P,且A⊆Q知集合A是由属于P且属于Q的元素构成,此时A可以为{2},{4},{2,4},故满足条件的集合A为⌀,{2},{4},{2,4}.
答案:⌀,{2},{4},{2,4}
9.导学号91000012已知集合A={x|x<-1,或x>4},B={x|2a≤x≤a+3},若B⫋A,求实数a的取值范围.
解:当B=⌀时,只需2a>a+3,即a>3,满足B⫋A.
当B≠⌀时,根据题意作出如图所示的数轴,
若B⫋A,需{■(a+3≥2a"," @a+3<"-" 1"," )┤或{■(a+3≥2a"," @2a>4"," )┤