Решение заданий:

1. 7(4a + 6) - 12a = 28a + 42 - 12a = (28a - 12a) + 42 = 16a + 42
2. 8x - 4(16 - 2x) = 8x - 64 + 8x = (8x + 8x) - 64 = 16x - 64
3. 1. 7(a - 4) + 0,6(6 - 2a) = 1,7a - 6,8 + 3,6 - 1,2a = (1,7a - 1,2a) + (3,6 - 6,8) = 0,5a - 3,2
4. 1. 5(8x - 6y) - (5y - 3x) \cdot 2,4 = 12x - 9y - 12y + 7,2x = (12x + 7,2x) + (-9y - 12y) = 19,2x - 21y
5. -(4,3x - 2,4) - (5,8 - 2,6x) = -4,3x + 2,4 - 5,8 + 2,6x = (-4,3x + 2,6x) + (2,4 - 5,8) = -1,7x - 3,4
6. $$\frac{8}{15}(\frac{3}{4}m - \frac{5}{16}n) - \frac{3}{20}(\frac{6}{3}m - \frac{4}{9}n) = \frac{8}{15} \cdot \frac{3}{4}m - \frac{8}{15} \cdot \frac{5}{16}n - \frac{3}{20} \cdot \frac{6}{3}m + \frac{3}{20} \cdot \frac{4}{9}n = \frac{2}{5}m - \frac{1}{6}n - \frac{3}{10}m + \frac{1}{15}n = (\frac{2}{5}m - \frac{3}{10}m) + (\frac{1}{15}n - \frac{1}{6}n) = \frac{4}{10}m - \frac{3}{10}m + \frac{2}{30}n - \frac{5}{30}n = \frac{1}{10}m - \frac{3}{30}n =$$ $$\frac{1}{10}m - \frac{1}{10}n =$$ $$\frac{1}{10}(m - n)$$ $$\frac{1}{10}m - \frac{1}{10}n$$