$\begin{array}{l}\phantom{\phantom{;}b\phantom{;}+2;}{-b^{2}+2b\phantom{;}-4\phantom{;}\phantom{;}}\\\phantom{;}b\phantom{;}+2\overline{\smash{)}-b^{3}\phantom{-;x^n}\phantom{-;x^n}+28\phantom{;}\phantom{;}}\\\phantom{\phantom{;}b\phantom{;}+2;}\underline{\phantom{;}b^{3}+2b^{2}\phantom{-;x^n}\phantom{-;x^n}}\\\phantom{\phantom{;}b^{3}+2b^{2};}\phantom{;}2b^{2}\phantom{-;x^n}+28\phantom{;}\phantom{;}\\\phantom{\phantom{;}b\phantom{;}+2-;x^n;}\underline{-2b^{2}-4b\phantom{;}\phantom{-;x^n}}\\\phantom{;-2b^{2}-4b\phantom{;}-;x^n;}-4b\phantom{;}+28\phantom{;}\phantom{;}\\\phantom{\phantom{;}b\phantom{;}+2-;x^n-;x^n;}\underline{\phantom{;}4b\phantom{;}+8\phantom{;}\phantom{;}}\\\phantom{;;\phantom{;}4b\phantom{;}+8\phantom{;}\phantom{;}-;x^n-;x^n;}\phantom{;}36\phantom{;}\phantom{;}\\\end{array}$

$-b^{2}+2b-4+\frac{36}{2+b}$