$\begin{array}{l}\phantom{\phantom{;}2x\phantom{;}+1;}{\phantom{;}3x^{2}-3x\phantom{;}+1\phantom{;}\phantom{;}}\\\phantom{;}2x\phantom{;}+1\overline{\smash{)}\phantom{;}6x^{3}-3x^{2}-x\phantom{;}-4\phantom{;}\phantom{;}}\\\phantom{\phantom{;}2x\phantom{;}+1;}\underline{-6x^{3}-3x^{2}\phantom{-;x^n}\phantom{-;x^n}}\\\phantom{-6x^{3}-3x^{2};}-6x^{2}-x\phantom{;}-4\phantom{;}\phantom{;}\\\phantom{\phantom{;}2x\phantom{;}+1-;x^n;}\underline{\phantom{;}6x^{2}+3x\phantom{;}\phantom{-;x^n}}\\\phantom{;\phantom{;}6x^{2}+3x\phantom{;}-;x^n;}\phantom{;}2x\phantom{;}-4\phantom{;}\phantom{;}\\\phantom{\phantom{;}2x\phantom{;}+1-;x^n-;x^n;}\underline{-2x\phantom{;}-1\phantom{;}\phantom{;}}\\\phantom{;;-2x\phantom{;}-1\phantom{;}\phantom{;}-;x^n-;x^n;}-5\phantom{;}\phantom{;}\\\end{array}$

$3x^{2}-3x+1+\frac{-5}{2x+1}$