|x| > 1?
Since we have a case of absolute values of integer values, the best way is to quickly test cases that will prove insufficiency.
1. (1 - 2x)*(1 + x) < 0
x = 0 => Inequality not satisfied
x = 1 => -2 < 0... satisfied
x= -1 => Inequality not satisfied
x = 2 => -9 < 0 ... satisfied.
Thus, |x| could be equal to 1 or greater than 1.
INSUFFICIENT
2. (1 - x)*(1 + 2x) < 0
x = 0 => Inequality not satisfied
x = 1 => Inequality not satisfied
x = -1 => -2 < 0 ... satisfied ...Don't forget negative values when testing cases!
x = 2 => -5 < 0 ... satisfied
Thus, |x| could be equal to 1 or greater than 1.
INSUFFICIENT
Both 1 and 2:
-1, 0 and 1 do not satisfy either one or both of our inequalities and are thus out of the domain. x = 2 satisfies both, as would any higher value.
Thus |x| > 1
SUFFICIENT
Pick C.
~Abhay
Believe those who are seeking the truth. Doubt those who find it. -- Andre Gide
