Jawabanmu

2014-06-08T16:20:13+07:00
N!/(n-7)! = 6!.n!/(n-5)!
1/(n-7)! = 6/(n-5)!
(n-5)! = 6(n-7)!
(n-5)(n-6)(n-7)!=6(n-7)!
n^2-11n+30=6
n^2-11n+24=0
(n-8)(n-3)=0
jdi n=3 atw 8