1.已知集合A=｛a,a+b,a+b² ｝,B=｛a,ax,ax²｝,A=B,求x的值.

题目

1.已知集合A=｛a,a+b,a+b² ｝,B=｛a,ax,ax²｝,A=B,求x的值.
2.已知集合A={x｜-2≤x≤5},B={x｜m+1≤x≤2m+1}.B含于A,求实数x的取值范围.
3.已知A=｛2,3｝,M={2,5,a²-3a+5},N={1,3,a-6a+10},A含于M,且A含于N,求实数a的值.

答案

1.已知集合A=｛a,a+b,a+b² ｝,B=｛a,ax,ax²｝,A=B,求x的值.由a+b=ax,得 x=1+(b/a) .(1)由a+b²=ax²,得x²=1+(b²/a).(2)故有 [1+(b/a)]²=1+(b²/a),化简得 2b/a+(b²/a...