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$$\frac{\left(8 - 3 x\right) \left(- \frac{8 - 3 x}{\left(x - 2\right)^{2}} - \frac{3}{x - 2}\right) \operatorname{sign}{\left(\frac{3 x - 8}{x - 2} \right)}}{3 x - 8} = 0$$
Solve this equationSolutions are not found,
function may have no extrema