Answer:
1
Step-by-step explanation:
Using the definition
n[tex]C_{r}[/tex] = [tex]\frac{n!}{r!(n-r)!}[/tex]
where n! = n(n - 1)(n - 2) × 3 × 2 × 1, note that 0! = 1
Given
9[tex]C_{9}[/tex] = [tex]\frac{9!}{9!(9-9)!}[/tex] = [tex]\frac{9!}{9!(0!)}[/tex] = [tex]\frac{9!}{9!}[/tex] = 1
