Please explain the marked step . Share with your friends Share 0 Lovina Kansal answered this Dear student We have,n!9! (n-9)!=n!8! (n-8)!⇒19! (n-9)!=18! (n-8)!⇒19×8!×(n-9)!=18! (n-8) (n-9)! ∵n!=n(n-1)(n-2).....3.2.1⇒9=n-8⇒n=17 Regards 0 View Full Answer