满足M∪{a1,a2,a3}={a1,a2,a3,a4,a5,a6}的集合M的个数是多少?

问题描述:

满足M∪{a1,a2,a3}={a1,a2,a3,a4,a5,a6}的集合M的个数是多少?

8个:M={a4,a5,a6},M={a1,a4,a5,a6},M={a2,a4,a5,a6},M={a3,a4,a5,a6}
M={a1,a2,a4,a5,a6},M={a1,a3,a4,a5,a6},M={a2,a3,a4,a5,a6}
M={a1,a2,a3,a4,a5,a6}