4. (9 marks) For each of the functions below (from Z to Z), indicate whether the function is onto, one-to-one, neither or both. If the function is not onto or not one- to-one, give an example showing why. If the function is bijective, find and shovw its inverse. a)f(x) =x-1 b) f(x) - x2 + 1 c) fix