$f ( x ) = \left\{ \begin{array} { r r } x ^ { 2 } + 3 & x < 0 \\3 - x & x \geq 0\end{array} \right.$

Essay

$f ( x ) = \left\{ \begin{array} { r r } x ^ { 2 } + 3 & x < 0 \\3 - x & x \geq 0\end{array} \right.$ Calculate $f ( - 1 ) , f ( 0 )$ and $f ( 2 )$