Question

Rezolvați ecuația: 8Combinari de X+1 luate cate 5=3Aranjamente de x luate cate 3

Answer 1

$\it C^5_{x+1} = 3 A^3_x \Rightarrow \dfrac{(x+1)!}{5!( x+1 - 5)!} =3\cdot\dfrac{x!}{(x-3)!}$