Which of these functions from $\mathbb{R}$ to $\mathbb{R}$ is one-one?

Explanation

1. 01

   $2a^{3} + 5 = 2b^{3} + 5$ gives $a^{3} = b^{3}$, so $a = b$: one-one.

2. 02

   The others repeat a value: $f(-1) = f(1) = 2$, $f(-1) = f(0) = 1$ and $f(0) = f(6) = 0$.