Anything to a negative power becomes the inverse with the coefficient to a positive power. For example, 3^-1 becomes 1/3^1 or just 1/3. 3^-2 would be 1/3^2 or 1/9.
The question is kind of all over the place. Can you clear it up a bit because it sound to me that all you have to do is simple addition and subtraction hun.