$$\left. \begin{array} { l } { f ( x ) = x + 2 \quad f ( x ) = x - 2 \quad f ( x ) = 2 x + 3 } \\ { f ( x ) = 2 x - 3 f ( x ) = x ^ { 2 } \quad f ( x ) = p x , \right.$$
$\left\{\begin{matrix}\\x=0\text{, }&\text{unconditionally}\\x\in \mathrm{C}\text{, }&f=-1\end{matrix}\right.$
$\left\{\begin{matrix}\\x=0\text{, }&\text{unconditionally}\\x\in \mathrm{R}\text{, }&f=-1\end{matrix}\right.$
