Желательно, фото с листа.

403) $\frac{a}{ab - 4b^2 } : \frac{4a^2}{a^2-8ab+16b^2} = \frac{a(a-4b)^2}{b(a-4b)*4a^2} = \frac{a-4b}{4ab}$

404) $\frac{a}{ab+2b^2} : \frac{4a^2}{a^2+4ab+4b^2} = \frac{a(a+2b)^2}{b(a+2b)*4a^2} = \frac{a+2b}{4ab}$

405) $\frac{a}{ab+6b^2} : \frac{3a^2}{a^2+12ab+36b^2} = \frac{a(a+6b)^2}{b(a+6b)*3a^2} = \frac{a+6b}{3ab}$

406) $\frac{a}{ab-5b^2} : \frac{5a^2}{a^2-10ab+25b^2} = \frac{a(a-5b)^2}{b(a-5b)*5a^2} = \frac{a-5b}{5ab}$

407) $\frac{5b^2}{a^2 - 49b^2} : \frac{b}{a^2+7ab} = \frac{5b^2*a(a+7b)}{(a-7b)(a+7b)*b} = \frac{5ab}{a-7b}$

408) $\frac{3b^2}{a^2 - 81b^2} : \frac{b}{a^2-9ab} = \frac{3b^2*a(a-9b)}{(a-9b)(a+9b)*b} = \frac{3ab}{a+9b}$

409) $\frac{5b^2}{a^2 - 81b^2} : \frac{b}{a^2+9ab} = \frac{5b^2*a(a+9b)}{(a-9b)(a+9b)*b} = \frac{5ab}{a-9b}$

410) $\frac{4b^2}{a^2 - 16b^2} : \frac{b}{a^2-4ab} = \frac{4b^2*a(a-4b)}{(a-4b)(a+4b)*b} = \frac{4ab}{a+4b}$

411) $\frac{8b^2}{a^2 - 36b^2} : \frac{b}{a^2-6ab} = \frac{8b^2*a(a-6b)}{(a-6b)(a+6b)*b} = \frac{8ab}{a+6b}$