kinghyts wrote:
Bunuel,
As per the explanation for the option 2) , x can be either +1 or -1. But since 2 sqrt(x^2) is a prime number, can we not assume that x can't be -1 because a prime number is "an integer that has no integral factors but itself and 1" which will not be the case if x is -1.
As per the explanation for the option 2) , x can be either +1 or -1. But since 2 sqrt(x^2) is a prime number, can we not assume that x can't be -1 because a prime number is "an integer that has no integral factors but itself and 1" which will not be the case if x is -1.
If you plug x=-1 into 2\sqrt{x^2} you'll still get a prime number:
2\sqrt{x^2}=2\sqrt{(-1)^2}=2\sqrt{1}=2=prime.