Data Sufficiency

Which of the x, 1/x, x^2 is the greatest?
1) x^2-x<0
2) |x|<1

*An answer will be posted in 2 days.

In the original condition, there is one variable, x. Hence, there is a high chance that D is the correct answer. In case of condition 1), from x(x-1)<0, we get 0<x<1. Hence, 1/x is always greater. The answer is unique and the condition is sufficient. In case of condition 2), from -1<x<1, if x=0.1, 1/x is the greatest. However, if x=-0.1, x^2 is always greatest. The answer is not unique and the condition is not sufficient. The correct answer is A.

- Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.
 

I put in Decimal numbers in both the equations and got certain answer in statement 1 and uncertain answer in statement 2. Is this the correct approach?