Question

resolva:
(n+3)! + (n+2)! = 15 . (n+1)!

Answer 1

Resposta:

(n+3)! + (n+2)! = 15 . (n+1)!

(n+3)(n+2)(n+1)! + (n+2)(n+1)! = 15 . (n+1)!

(n+3)(n+2)+ (n+2)= 15

n²+2n+3n+6+n+2=15

n²+6n-7=0

n'=-7  ..não existe fatorial de número negativo

n=1  é a resposta