Hitunglah:a. 9 P 1-8 P 0+9 P 1 b. 9 P 3-8 P 2+9 P 3

a. 17, b. 952

Pembahasan

Untuk menghitung permutasi:
 a. $9P1 - 8P0 + 9P1$
   Rumus permutasi $nP r = \frac{n!}{(n-r)!}$.
   $9P1 = \frac{9!}{(9-1)!} = \frac{9!}{8!} = 9$.
   $8P0 = \frac{8!}{(8-0)!} = \frac{8!}{8!} = 1$.
   $9P1 = 9$.
   Jadi, $9 - 1 + 9 = 17$.

 b. $9P3 - 8P2 + 9P3$
   $9P3 = \frac{9!}{(9-3)!} = \frac{9!}{6!} = 9 \times 8 \times 7 = 504$.
   $8P2 = \frac{8!}{(8-2)!} = \frac{8!}{6!} = 8 \times 7 = 56$.
   $9P3 = 504$.
   Jadi, $504 - 56 + 504 = 952$.