Question

simplifique as frações:

Answer 1

a) 6!/3!= 6x5x4x3!/3! = 6x5x4 = 120

b) = 5!*8! / 4!*7! = 5x4! * 8*7! /  4!*7! = 5x8  = 40 e o 4!*7! se anulam

c) n! / (n-1)! = n*(n-1)! / (n-1)!  = n

d) n!  / (n+2)*n+1)! *n! =  1/ n+2*n+1 = 1/ n²+n+2n+2 = 1/n²+3n+2