How do you simplify #.(a/b^3)^-3#?
Have a look:
You can consider that your negative cube is going to be applied to both numerator and denominator.
So you get:
you now use the rule of exponents where
At this point you can use (although I am not sure about the usefulness of it) the idea that a negative exponent sends your base to another "floor"; so if, say,
In your case you can write: