Bunuel wrote:

Is x > 0 ?

(1) x^3 < x

(2) x is even.

we don't know whether x is integer or fraction or negative or positive.

statement 1 :\(x^3\)<x. this statement is true when x is fraction or negative. So, we can determine whether x>0 or not.

statement 2 : x is even. but here x can also be negative or positive. Not sufficient.

combining (1+2): analyzing both statements we understand that x is negative and even integer.

Thus, x is not positive for sure. So, the correct answer is C.