Question

se (n + 4)! + (n + 3)! = 15(n + 2)!​

Answer 1

(n + 4)! + (n + 3)! = 15(n + 2)!

(n+4)(n+3)(n+2)! + (n+3)(n+2)! =15(n+2)!

(n+4)(n+3) + (n+3) =15

n²+7n+12 + n+3 - 15 = 0

n² +8n = 0

n(n+8)=0 ==> n= 0 ✓

n+8=0 => n=-8 (NÃO SERVE)