- $ \\\mathbb{R}\\\backslash \\\left\\\{ 1 \\\right\\\}$.
- $ \\\mathbb{R}\\\backslash \\\left\\\{ 3 \\\right\\\}$.
- $ \\\mathbb{R}\\\backslash \\\left\\\{ 2 \\\right\\\}$.
- $ \\\left( {1; + \\\infty } \\\right)$.