Решение:
$$\frac{log_{2}12.8 - log_{2}0.8}{5^{log_{25}16}} = \frac{log_{2}\frac{12.8}{0.8}}{5^{log_{5^{2}}4^{2}}} = \frac{log_{2}16}{5^{\frac{2}{2}log_{5}4}} = \frac{log_{2}2^{4}}{5^{log_{5}4}} = \frac{4}{4} = 1$$
Ответ: 1