We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website. cookie policy and privacy policy.
 
+0  
 
+1
171
1
avatar+294 

Please give me a detailed solution for the question

Let n > 18 be a positive integer such that n-1 and n+1 both are prime .

Prove that n has at least 8 different positive factors .

 Nov 9, 2018
 #1
avatar
0

42 =2 x 3 x 7 =3 "Prime Factors"
Total divisors =The exponent of each "Prime Factor" + 1, all multiplied together: (1+1) x (1+1)x(1+1) =8 divisors:
1 | 2 | 3 | 6 | 7 | 14 | 21 | 42 (8 divisors), or factors.
42 - 1 =41 Prime number
42+1 =43 Prime number.

 Nov 9, 2018
edited by Guest  Nov 9, 2018

7 Online Users