Answer:
504
Step-by-step explanation:
Using the definition
n[tex]P_{r}[/tex] = [tex]\frac{n!}{(n-r)!}[/tex]
where n! = n(n - 1)(n - 2).... × 3 × 2 × 1
Thus
9[tex]P_{3}[/tex] = [tex]\frac{9!}{6!}[/tex] ← cancel the terms of 6! on numerator/denominator, leaving
= 9 × 8 × 7 = 504
