Why can a ghost solve the equation x square root equals negative four but not the equation x square root equals four?

A ghost can "solve" the equation ( x \sqrt{} = -4 ) in a figurative sense because the equation implies the presence of complex numbers, where ( x ) can take on imaginary values. Specifically, if we interpret ( x \sqrt{} ) as ( x ), then we can find a solution using ( x = -2i ). However, in the case of ( x \sqrt{} = 4 ), the solutions are real and positive, which might be outside the ghost's ethereal realm, suggesting that the ghost prefers the complexity of imaginary solutions over straightforward real ones.