Question

6 P(n-5) ×A(n-2) cite 5 egal n!     sa se afle numarul natural n

Answer 1

[tex]6\cdot(n-5)!\cdot \frac{(n-2)!}{(n-7)!}= n!\\ 6\cdot(n-7)!(n-6)(n-5)\cdot \frac{(n-2)!}{(n-7)!}= (n-2)!(n-1)n\\ 6\cdot(n-6)(n-5)= (n-1)n\\ n=4[/tex]