Question

Se (n + 4)! + (n + 3)! = 15(n + 2)!, então:
a) n = 4
b) n = 3
c) n = 2
d) n = 1
e) n = 0

Answer 1

(n+4).(n+3).(n+2)! + (n+3).(n+2)! = 15(n+2)! -> n^2 + 3n + 4n + 12 + n + 3 = 15 -> n^2 + 8n = 0 -> n(n + 8) = 0 -> n = 0 ou n = -8 -> e)