Question

1.tentukan nilai n dari (n-1)! / (n-3)! = 72 !
2.sederhanakan:
a. (n+1)! / n!
b. (n-k+1)! / (n-k-1)!

Answer 1

1. (n-1) ! / (n-3)! = 72
(n-1) (n-2) (n-3)! / (n-3) ! = 72
(n-1) (n-2) =72
n²-3n+2 = 72
(n-10) (n+7) 
n= 10 

2. (n-k+1)/(n-k-1)!
(n-k+1) (n) (n-k-1)! / (n-k-1)!
(n-k+1) (n)
n²-kn-n

#maafkalausalahyah

Answer 2

No. 1
(n-1)(n-2)(n - 3)!/(n - 3)! = 72
(n - 1)(n - 2) = 72
n² - 3n + 2 - 72 = 0
n² - 3n - 70 = 0
(n - 10)(n + 7) = 0
n₁ = 10  n₂ = -7
(nilai n yang digunakan hanya n₁ = 10 karena n₂ = -7 bernilai negatif)