Easy question on differentiation

Hi I have a really easy question that I do not understand here.

y = (2sqrt(x))/(1-x)),
and for dy/dx I got (x+1)/(sqrt(x)(1-x)^2)

Here's what I'm confused about,
For what values of x is dy/dx zero.

My answer will be -1 since if the numerator is zero, dy/dx will be zero but the answer says never..

Thank you for your help!!

Notice that the domain of your derivative is

How did you know that the domain of this derivative is as such?

Thank you!

Square roots are only defined for nonnegative values, and denominators can't ever be 0.