n! / (n-2)! = 2 Tentukan nilai n?

n! / (n-2)! = 2
n! / (n-2)(n-1)n! = 2
1 / (n - 2)(n - 1) = 2
1 = 2(n - 2)(n - 1)
1 = 2(n² - 3n + 2)
1 = 2n² - 6n + 4
2n² - 6n + 3 = 0

a = 2
b = -6
c = 3

X1,2 = -b ± √(b² - 4ac) / 2a
X1,2 = 6 ± √(-6² - 4.2.3) / 2.2
X1,2 = 6 ± √(36 - 24) / 4
X1,2 = 6 ± √12 / 4
X1,2 = 2(3 ± √3) / 4
X1,2 = (3 ± √3) / 4

X1 = (3 + √3) / 4
X2 = (3 - √3) / 4

maka n = (3 + √3) / 4

semoga berguna +_+