Question

C (n,2)= 28 maka p(n,2) sama dengan?

Answer 1

C (n,2) = 28
C (n,2) = n!/2!(n-2)!
       28 = n!/2(n-2)!
       56 = n(n-1)
        0 = n² - n - 56
        0 = (n-8)(n+7)
        n = 8 atau n = -7(ambil yg positif aja)

n= 8

P(8,2) = 8!/(8-2)!
           = 8!/6!
           = 7.8
           = 56

Answer 2

C (n,2) = 28
maka p(n,2) = 28x2 = 56