Question

combinacao de 12,3 não consigo desenvolver

Answer 1

Cn,p = n!/(p!(n-p)!

C12,3 = 12!/3!9! = 12.11.10.9!/3.2.1.9! = 12.11.10/6 = 220 = 

Answer 2

$\mathrm{C_{n;k}=\cfrac{n!}{k!(n-k)!}\ \to\ C_{12;3}=\cfrac{12!}{3!(12-3)!}}\\\\ \mathrm{C_{12;3}=\cfrac{12!}{3!.9!}\ \to\ C_{12;3}=\cfrac{12.11.10.9!}{6.9!}}\\\\ \mathrm{C_{12;3}=2.11.10}\ \to\ \mathbf{C_{12;3}=220}$