Question

(n-r+1) n!/(n-r+1)!=n!/(n-r)!

Answer 1

LHS
=(n-r+1)n!/(n-r+1)!
=(n-r+1)n!/(n-r+1)(n-r)!
=n!/(n-r)!
=RHS
PROVED

Answer 2

(n-r+1)n!/(n-r+1)!

Both (n-r+1)! will be cancelled

so the remaining is n!

WE KNOW THAT, n! =n!/(n-r)!

so

n!/(n-r)!=n!/(n-r)!

L.H.S =R.H.S

HENCE PROVED

THANK YOU!!