In: Advanced Math
For each pair a, b with a ∈ R − {0} and b ∈ R, define a function fa,b : R → R by fa,b(x) = ax + b for each x ∈ R.
(a) Prove that for each a ∈ R − {0} and each b ∈ R, the function fa,b is a bijection.
(b) Let F = {fa,b | a ∈ R − {0}, b ∈ R}. Prove that the set F with the operation of composition of functions is a non-abelian group. You may assume that function composition is associative.