Let Z denote the set of integers, then function f: Z → Z defined as f ( x )= x^3-1 is:

Let $\displaystyle Z$ denote the set of integers, then function $\displaystyle \mathrm{f}: Z \rightarrow Z$ defined as $\displaystyle \mathrm{f}(\mathrm{x})=\mathrm{x}^{3}-1$ is :