Question

Tolong jawab ya peluang

Answer 1

(n + 1)! = 120
(n - 2)!

(n + 1) * (n) * (n-1) * (n - 2)! = 120
             (n - 2)!

(n + 1)(n)(n-1) = 120
(n + 1)(n² - n) = 120
n³ - n² + n² - n = 120
n³ - n = 120
n³ - n = 120
n³ - n - 120 = 0

(n - 5)(n² + 5n + 24)

n - 5 = 0
n = 5

n² + 5n + 24
b² - 4ac
= 5² - 4(1)(24)
= 25 - 96
= -71
akarnya tidak real, jadi gunakan n = 5

Jadi nilai n = 5