Ответ: 1. 8! = 1·2·3·4·5·6·7·8 = 403202. C_n^m = n!/(m!(n-m)!); n = 20; m = 5:C_20^5 = 20!/(5!(20-5)!) = 20!/(5!·15!) = 16·17·18·19·20 / 1·2·3·4·5 = 155043. 5·4·3·2 = 1204. 5! = 1·2·3·4·5 = 1205. А_n^m = n!/(n-m)!; n = 6; m = 2:А_6^2 = 6!/(6-2)!) = 6!/4! = 5·6 = 30
Источник znanija.site