Й) $$74,7·\frac{2}{21}+(-105,3)·2\frac{3}{7}-(-105,3)·\frac{2}{21}-2\frac{3}{7}·74,7$$

Й) Выполним действия:

1) $$74,7 \cdot \frac{2}{21} = \frac{747}{10} \cdot \frac{2}{21} = \frac{249}{5} \cdot \frac{2}{7} = \frac{498}{35}$$

2) $$-105,3 \cdot 2\frac{3}{7} = -\frac{1053}{10} \cdot \frac{17}{7} = -\frac{17901}{70}$$

3) $$\left(-\frac{1053}{10}\right) \cdot \left(-\frac{2}{21}\right) = \frac{1053}{10} \cdot \frac{2}{21} = \frac{351}{5} \cdot \frac{2}{7} = \frac{702}{35}$$

4) $$\left(-\frac{17}{7}\right) \cdot \frac{747}{10} = -\frac{12699}{70}$$

5) $$\frac{498}{35} - \frac{17901}{70} + \frac{702}{35} - \frac{12699}{70} = \frac{498 \cdot 2}{35 \cdot 2} - \frac{17901}{70} + \frac{702 \cdot 2}{35 \cdot 2} - \frac{12699}{70} = \frac{996}{70} - \frac{17901}{70} + \frac{1404}{70} - \frac{12699}{70} = \frac{996 - 17901 + 1404 - 12699}{70} = \frac{-28200}{70} = -402,85714...$$

Ответ: -402,86