Question 183534: The problem I am stuck on is the one listed below:
Find a counter example to the statement " the square of a number added to the sum of the number and five is a prime number".
Please help me to understand and work out this problem correctly.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Find a counter example to the statement " the square of a number added to the sum of the number and five is a prime number".
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Let the number be "x":
x^2 + x + 5 = prime for all values of x ????
Let x = 4
16 + 4 + 5 = 25, which is not prime is a counter-example.
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If x = 5 you get 35, which is not prime
If x = 9 you get 95, which is not prime
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Cheers,
Stan H.
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