$\begin{array}{l}\phantom{\phantom{;}x^{2}-3x\phantom{;}+1;}{\phantom{;}3x\phantom{;}+4\phantom{;}\phantom{;}}\\\phantom{;}x^{2}-3x\phantom{;}+1\overline{\smash{)}\phantom{;}3x^{3}-5x^{2}-7x\phantom{;}-3\phantom{;}\phantom{;}}\\\phantom{\phantom{;}x^{2}-3x\phantom{;}+1;}\underline{-3x^{3}+9x^{2}-3x\phantom{;}\phantom{-;x^n}}\\\phantom{-3x^{3}+9x^{2}-3x\phantom{;};}\phantom{;}4x^{2}-10x\phantom{;}-3\phantom{;}\phantom{;}\\\phantom{\phantom{;}x^{2}-3x\phantom{;}+1-;x^n;}\underline{-4x^{2}+12x\phantom{;}-4\phantom{;}\phantom{;}}\\\phantom{;-4x^{2}+12x\phantom{;}-4\phantom{;}\phantom{;}-;x^n;}\phantom{;}2x\phantom{;}-7\phantom{;}\phantom{;}\\\end{array}$

$3x+4+\frac{2x-7}{x^2-3x+1}$