For each of the following functions /: Z -> Z, determine whether the function is one-to-one and whether it is onto. If the function is not onto, determine the range /(Z).
(a) f{x) = x + 7
(b) fix) = 2x - 3
(c) f(x) = - x + 5
(d) f(x) = x2
(e) f(x) = x2 + x
(f) (x) = x3