Question

urgente!!!!!
Gente é so para responder a 1 2 e 4 .

Answer 1

1)
a) n!/(n-1)! = n x (n-1)! / (n-1)! = n

b) n! / (n-2)! = nx (n-1) x (n-2)! / (n-2)! = n x (n-1) = n^2-n