Question

Решение выражений с факториалами:

70!/68!*5!

8!+9!/7!

12!-10!/11!

(n+2)!/(n-1)!

(n-2)!/(n-4)!

Answer 1

70!/68!*5! = 68!*69*70/ 67!*5 = 69*70/120 = 69*7/12= 483/12.
8!+9!/7!= 8*7! +8* 9*7! / 7! = 7!(8+72) / 7! = 81 .

12!-10!/11! = 11*12*10! - 10! / 11*10! = 10!(132- 1) / 11* 10! = 131/11.

(n+2)!/(n-1)! = n*(n+1)(n+2)*(n-1)! / (n-1)! = n(n+1)(n+2).

(n-2)!/(n-4)! = (n-2)*(n-3)*(n-4)! / (n-4)! = (n-2)(n-3)