$\begin{array}{l}\phantom{\phantom{;}z\phantom{;}+4;}{\phantom{;}z^{2}-7z\phantom{;}+28\phantom{;}\phantom{;}}\\\phantom{;}z\phantom{;}+4\overline{\smash{)}\phantom{;}z^{3}-3z^{2}\phantom{-;x^n}+7\phantom{;}\phantom{;}}\\\phantom{\phantom{;}z\phantom{;}+4;}\underline{-z^{3}-4z^{2}\phantom{-;x^n}\phantom{-;x^n}}\\\phantom{-z^{3}-4z^{2};}-7z^{2}\phantom{-;x^n}+7\phantom{;}\phantom{;}\\\phantom{\phantom{;}z\phantom{;}+4-;x^n;}\underline{\phantom{;}7z^{2}+28z\phantom{;}\phantom{-;x^n}}\\\phantom{;\phantom{;}7z^{2}+28z\phantom{;}-;x^n;}\phantom{;}28z\phantom{;}+7\phantom{;}\phantom{;}\\\phantom{\phantom{;}z\phantom{;}+4-;x^n-;x^n;}\underline{-28z\phantom{;}-112\phantom{;}\phantom{;}}\\\phantom{;;-28z\phantom{;}-112\phantom{;}\phantom{;}-;x^n-;x^n;}-105\phantom{;}\phantom{;}\\\end{array}$

$z^{2}-7z+28+\frac{-105}{z+4}$