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 3 years ago
:Help...........for how many positive integers n is n^3 8n^2+20n13 a prime number??
 3 years ago
:Help...........for how many positive integers n is n^3 8n^2+20n13 a prime number??

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King
 3 years ago
Best ResponseYou've already chosen the best response.0how watever i get is not a prime number

King
 3 years ago
Best ResponseYou've already chosen the best response.0but then ii have to plug in millions of values

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1(n^3 8n^2+20n13) a prime number

King
 3 years ago
Best ResponseYou've already chosen the best response.0for n i will have to put millions of values to find how may n positive integers satisfy n^3 8n^2+20n13 to be a prime number

King
 3 years ago
Best ResponseYou've already chosen the best response.0anything i can do to narrow down the possobilities

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1ok see for 2 it is prime number

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1\[(x1) \times [(x7)x + 13]\]

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1now see the first term is (x1). and other than 2 no other even number is a prime number right

King
 3 years ago
Best ResponseYou've already chosen the best response.0no n does not have to be a prime number n^3 8n^2+20n13 has to be a prime number

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1yeah i know (x−1)×[(x−7)x+13] it has to be prime

King
 3 years ago
Best ResponseYou've already chosen the best response.0yup so x can be anything greater or equal to 2

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1first term is (x1) and two is the only even prime number.

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1but if u will subtract 1 from any other prime number the resultant will be divisible by 2

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1it means that for any odd integer other than 3 u will not get a prime number

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1also the number cannot be graeter than 7

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1so u are having a limited space to work out that is from 1 to 7

King
 3 years ago
Best ResponseYou've already chosen the best response.0yes sheg u got it so answer is n=2,3,4

King
 3 years ago
Best ResponseYou've already chosen the best response.0wait why cant it be greater than 7?

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1try any number u will get the answer

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1odd numbers cannot be included ok thats true

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1as i had told u any odd number subtracted by one will result in even number so it will be divisible by 2.........do u accept it or not

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1so 323 is not a prime number

King
 3 years ago
Best ResponseYou've already chosen the best response.0gtg shall come bak in 15 min

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1for n = 20 it should be equal to 5187

sheg
 3 years ago
Best ResponseYou've already chosen the best response.120^3  8*20^2 + 20*20 13 =8000  3200 + 400 13 = 8400  3213 = 5187

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1dear i had told u for no value greater than 7 it would fit

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1and both 1443 and 5187 is divisible by 3

King
 3 years ago
Best ResponseYou've already chosen the best response.0i am bak so what to do now?

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1for no value greater than 7 that too even number it will not be a prime number

sheg
 3 years ago
Best ResponseYou've already chosen the best response.1http://www.wolframalpha.com/input/?i=x^38x^2%2B20x13+where+x+%3D+20 visit this website and plug in different value of x u will get the answer
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