$f\left(x\right)=0gdyx=2\leftarrow m.zerowe$

$f\left(x\right)>0gdyx=3$ $f\left(x\right)>0gdyx=3$

$f\left(x\right)<0gdyx\in \left\{-1,0,1\right\}$

$f\uparrow$

$f_{\max }=1$

$f_{\min }=-3$

$f\left(-1\right)=-3$

$f\left(3\right)=1$