Question

O valor de n na equação n!/(n-2)!= n!/3!(n-3)! e?
Alternativas.
A( )2
B( )4
C( )6
D( )8
E( )10
?

Answer 1

n!/(n - 2)! = n!/3!(n - 3)!

n(n - 1)(n - 2)!/(n - 2)! = n(n - 1)(n - 2)(n - 3)!/3!(n - 3)!

n(n - 1) = n(n - 1)(n - 2)/3!

n(n - 1)/n(n - 1) = (n - 2)/3!

1 = (n - 2)/3!

3! = (n - 2)

3 . 2 = (n - 2)

6 = n - 2

n = 8

D()8.