Question

(x+1)! = 720 (x+1)factorial = 720

Answer 1

   
(x+1)! = 720
Descompunem pe 720 in factori primi.

$720 = 2^4 \times 3^2 \times 5$

Reorganizam factorii pentru a obtine un factorial.

[tex]720 = 1 \times 2 \times 3 \times 2^2 \times 5 \times (2 \times 3) \\ 720 = 1 \times 2 \times 3 \times 4 \times 5 \times 6 \\ \Longrightarrow~~720 = 6! \\ \\ (x+1)! = 6! \\ x+1 = 6 \\ x = 6-1 = \boxed{5}[/tex]