The domain of g^(-1)(x) is the range of g(x), and the range of g^-1(x) is the domain of g(x).
This is because g^-1(x) is a reflection of g(x) in the line y=x, so all the x coordinates switch to be the y coordinates, and the y coordinates become the x coordinates (e.g. if a point on g(x) is (2,4), this would translate to (4,2) on g^-1(x)). Hence the range and domain would also switch around.