Question

Resolva a equação: (n-2)!=2.(n-4)!

Answer 1

(n-2)!= 2(n-4)!
[(n-2).(n-3).(n-4)!] /(n-4)!=2
corta (n-4)!
(n-2)(n-3)= 2
n^2 -5n + 6 = 2
n^2 -5n + 4= 0
delta = 25 -4. 1.4
delta= 9
n=(5+ 3)/2
n=4