第3题的(1)(2)小题怎么做

2025-05-18 16:06:23
推荐回答(1个)
回答(1):

解,(1)C(8,6)
=C(8,2)
=8x7/2
=48
(2)C(9,8)C(10,9)
=C(9,1)C(10,1)
=9x10
=90