Question

factoriales

(n+1)! +n!              18!

(n-2)! +(n-1)!     =   17!

Answer 1

(n+1)! +n!              18!

(n-2)! +(n-1)!     =   17!

 

paraece una fraccion em ambos lados

(n+1)! +n!          n!(n+1+1)          n!(n+2)     (n-1)!(n+2)      (n-1)(n+2)=18

(n-2)! +(n-1)!=(n-2)!(n-1+1)=     (n-2)!(n) =     (n-2)!     = 

 

n2+n-2=18

n2+n-20=0

(n+5)(n-4)=0

n=-5

n=4