a) ($$\frac{1}{14} - \frac{2}{7}$$) : (-3) - 6$$\frac{1}{13}$$ : (-6$$\frac{1}{13}$$); б) (7 - 8$$\frac{4}{5}$$) ⋅ 2$$\frac{7}{9}$$ - 15 : ($$\frac{1}{8}$$ - $$\frac{3}{4}$$); в) (204,12 : 10,5 - 3,2 ⋅ 1,2) ⋅ 6$$\frac{1}{2}$$ + 7 : 2$$\frac{1}{3}$$.

а) Разбираемся:

• \(\frac{1}{14} - \frac{2}{7} = \frac{1}{14} - \frac{4}{14} = -\frac{3}{14}\)
• \(-\frac{3}{14}\) : (-3) = \(-\frac{3}{14}\) : \(-\frac{3}{1}\) = \(\frac{3}{14} \cdot \frac{1}{3} = \frac{1}{14}\)
• 6$$\frac{1}{13}$$ : (-6$$\frac{1}{13}$$) = -1
• \(\frac{1}{14} - (-1) = \frac{1}{14} + 1 = \frac{1}{14} + \frac{14}{14} = \frac{15}{14}\)

Ответ: $$\frac{15}{14}$$

б) Разбираемся:

• 7 - 8$$\frac{4}{5}$$ = \(\frac{7}{1} - \frac{44}{5} = \frac{35}{5} - \frac{44}{5} = -\frac{9}{5}\)
• 2$$\frac{7}{9} = \frac{25}{9}\)
• (-\frac{9}{5}) ⋅ \(\frac{25}{9} = -\frac{9 \cdot 25}{5 \cdot 9} = -\frac{225}{45} = -5\)
• $$\frac{1}{8} - \frac{3}{4} = \frac{1}{8} - \frac{6}{8} = -\frac{5}{8}\)
• 15 : \(-\frac{5}{8}\) = \(15 \cdot (-\frac{8}{5}) = -\frac{15 \cdot 8}{5} = -\frac{120}{5} = -24\)
• -5 - (-24) = -5 + 24 = 19

Ответ: 19

в) Разбираемся:

• 204,12 : 10,5 = 19,44
• 3,2 ⋅ 1,2 = 3,84
• 19,44 - 3,84 = 15,6
• 6$$\frac{1}{2} = \frac{13}{2} = 6.5\)
• 15,6 ⋅ 6,5 = 101,4
• 2$$\frac{1}{3} = \frac{7}{3}\)
• 7 : \(\frac{7}{3} = 7 \cdot \frac{3}{7} = 3\)
• 101,4 + 3 = 104,4

Ответ: 104,4