Pls solve question 7 Share with your friends Share 1 Lovina Kansal answered this Dear student Let n,n+1,n+2 be three consecutive natural numbers.We have to show that n3+n+13+n+23 is divisible by 9.For n=1: 13+23+33=1+8+27=36 which is divisible by 9.Assume that P(k) is true.ie k3+k+13+k+23 is divisible by 9.Then , we have,=k+13+k+23+k3+3C1k23+3C2k32+3C333=k+13+k+22+k3+9k2+27k+27=k3+k+13+k+23+9k2+3k+3k3+k+13+k+23 is divisible by 9 and 9k2+3k+3 is divisible by 9.⇒k+13+k+23+k+33 is divisible by 9.Hence assuming P(k) is true, P(k+1) is also true. Therefore, P(n) is true for all n≥1. Regards 0 View Full Answer