Помогите решить номер 42 срочно надо

Решите задачу:

$\frac{x^6+x^4}{x^4+x^2}= \frac{x^4(x^2+1)}{x^2(x^2+1)}=x^2\\\\ \frac{y^6-y^8}{y^4-y^2}= \frac{y^6(1-y^2)}{y^2(y^2-1)}=- \frac{y^6(y^2-1)}{y^2(y^2-1)}=-y^4\\\\ \frac{b^7-b^{10}}{b^5-b^2}= \frac{b^7(1-b^3)}{b^2(b^3-1)}=- \frac{b^7(1-b^3)}{b^2(1-b^3)}=-b^5 \\\\ \frac{c^6-c^4}{c^3-c^2}= \frac{c^4(c^2-1)}{c^2(1-c)}=-\frac{c^4(c^2-1)}{c^2(c-1)}=- \frac{c^4(c-1)(c+1)}{c^2(c-1)}=-c^2(c+1)$