In order to find the extrema, we need to solve the equation
$$\frac{d}{d x} f{\left(x \right)} = 0$$
(the derivative equals zero),
and the roots of this equation are the extrema of this function:
$$\frac{d}{d x} f{\left(x \right)} = $$
the first derivative$$\frac{\left(3 - 2 x\right) \left(\left(11 x + \left(x^{3} - 6 x^{2}\right)\right) - 6\right)}{\left(\left(x^{2} - 3 x\right) + 2\right)^{2}} + \frac{3 x^{2} - 12 x + 11}{\left(x^{2} - 3 x\right) + 2} = 0$$
Solve this equationSolutions are not found,
function may have no extrema