Let  $f\left(x\right)=\frac{x^3-6x^2+11x-6}{x^3+6x^2+11x+6}.$  Find the sum of all integral values of  $x$  which satisfy  $f\left(x\right)<0.$

 $f\left(x\right)=\frac{(x-1)(x-2)(x-3)}{(x+1)(x+2)(x+3)}<0$
Using wavy curve

 $\Rightarrow x\in (-3,-2)\cup (-1,1)\cup (2,3)$
$\Rightarrow$  only $x=0$  is the integral solution