Question

resolva a equação: A n,2 = A n - 2,2 + 14

Answer 1

Bom dia Lais

A(n,2) = A(n - 2,2) + 14 

A(n.k) = n!/(n - k)!

A(n,2) = n!/(n - 2)! = n*(n - 1)*(n - 2)!/(n - 2)! = n*(n - 1)

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

n*(n - 1) = (n - 2)*(n - 3) + 14

n² - n = n² - 5n + 6 + 14

5n - n = 20

4n = 20

n = 5