D is false.
-1 = -(-1)
When you negate the negative on the left, you get a positive 1, not a negative 1.
Answer:
B. 
Hope this helped. A brainliest would be very much appreciated. (I need 4 brainliest so I can level up) :)
Answer:

Step-by-step explanation:
The fractional exponent m/n is often translated to radical form as ...
![x^{\frac{m}{n}}=\sqrt[n]{x^m}](https://tex.z-dn.net/?f=x%5E%7B%5Cfrac%7Bm%7D%7Bn%7D%7D%3D%5Csqrt%5Bn%5D%7Bx%5Em%7D)
In this case, I find it easier to evaluate as ...
![x^{\frac{m}{n}}=(\sqrt[n]{x})^m=\boxed{(\sqrt{9})^3=3^3=27}](https://tex.z-dn.net/?f=x%5E%7B%5Cfrac%7Bm%7D%7Bn%7D%7D%3D%28%5Csqrt%5Bn%5D%7Bx%7D%29%5Em%3D%5Cboxed%7B%28%5Csqrt%7B9%7D%29%5E3%3D3%5E3%3D27%7D)
Y-y
——-
X-x
21-9=12
5-(-1) =6
So the answer is D