16) $$\frac{5ab(8a-3b)}{10a^2b^2(3b-8a)} = -\frac{5ab(3b-8a)}{10a^2b^2(3b-8a)} = -\frac{1}{2ab}$$
$$\frac{5ab(8a-3b)}{10a^2b^2(3b-8a)} = -\frac{5ab(3b-8a)}{10a^2b^2(3b-8a)} = -\frac{1}{2ab}$$
Ответ: -1/2ab