1. For each of the following maps, where f : Z×Z→Z, determine whether f is:
i.) onto and one-to-one
ii.) onto but not one-to-one
iii.) not onto but one-to-one
iv.) neither onto nor one-to-one
v.) not a function
a) f (x, y) = 3x2 −2y
b) f (x, y) = y! + x
c) f (x, y) = 2x ∗3y
d) f (x, y) = x −y
e) f (x, y) =|x |+y