Which of these describes $f : \mathbb{R} \to \mathbb{R}$, $f(x) = x^{2} + 2x$?

Explanation

1. 01

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

2. 02

   $x^{2} + 2x = (x + 1)^{2} - 1 \ge -1$, so $-2$ is never reached: not onto.