Which of these describes $f : \mathbb{R} \to \mathbb{R}$, $f(x) = \lvert x \rvert + x$?

Explanation

1. 01

   $f(-1) = f(-2) = 0$: not one-one.

2. 02

   $f(x) = 2x$ for $x \ge 0$ and 0 otherwise, so it is never negative: not onto.