1. Prove the following statement. If x is an even integer, then 4x+5 is an odd integer. (using format x = some k and so on)
2. Let A = {a1, a2} and B = {b1, b2, b3}. Let the function f:A → B be given by the following set of ordered pairs: f = {(a1,b2),(a2,b3)}.
List as a set of ordered pairs a function g:B → A with the property that for all a in A g(f(a)) = a, and show that this property holds. HINT: Think of g as "undoing" what f does.