Question

Find if f(x) = (3x - 4)/(x² + 1) is one-to-one.

Answer 1

 The domain of f(x) is whole of set R.

which is quadratic in x if y ≠ 0. Thus, this gives two real values of x if

9 − 4y(y + 4) > 0

and if y ∈ (−9/2, 1/2). Therefore, f is not one-to-one function.