jmaynardj wrote:

I will take from what was said above but come to the E conclusion:

1) equivalent to x*(1-x^2)=x*(1-x)*(1+x) < 0 -> *** Here is where I differ. This conclusion gives us -1 < x < 1 but x /= 0. So still insufficient, but it changes the final answer.

2) (x-1)*(x+1) < 0 -> x is between -1 and 1 -> insufficient

The key to this problem is seeing that 1 and 2 are essentially the same information except 1 excludes 0.

So now we combine the two. Both answers allow for a positive or negative result. Try -1/2 or +1/2. So E is the correct answer.

Ok so 1) equivalent to x*(1-x^2)=x*(1-x)*(1+x) < 0 -> *** Here is where I differ. This conclusion gives us -1 < x < 1 but x /= 0. So still insufficient, but it changes the final answer.

has to be changed to -1 < x < 0 or x > 1. So by combining the two ranges from 1 & 2 you have only -1 < x < 0. Therefore C. Great problem. Hope I don't see anything quite so hard on the real test