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

$-x^{2}-2x-1+\frac{-4}{-3x+1}$