The sum of the absolute minimum and the absolute maximum values of the function \( f(x)=\left|3x-x^{2}+2\right|-x \) in the interval \( [-1,2] \) is:
\( \dfrac{\sqrt{17}+3}{2} \)
\( \dfrac{\sqrt{17}+5}{2} \)
\( 5 \)
\( \dfrac{9-\sqrt{17}}{2} \)