а) $$\frac{15}{19} - \frac{7}{19} - \frac{1}{19} = \frac{15-7-1}{19} = \frac{7}{19}$$
б) $$7\frac{5}{14} - 3\frac{11}{14} = 6\frac{19}{14} - 3\frac{11}{14} = (6-3) + (\frac{19}{14} - \frac{11}{14}) = 3 + \frac{8}{14} = 3\frac{4}{7}$$
в) $$5 - 2\frac{4}{11} = 4\frac{11}{11} - 2\frac{4}{11} = (4-2) + (\frac{11}{11} - \frac{4}{11}) = 2 + \frac{7}{11} = 2\frac{7}{11}$$
г) $$8\frac{2}{9} - 2\frac{1}{9} = (8-2) + (\frac{2}{9} - \frac{1}{9}) = 6 + \frac{1}{9} = 6\frac{1}{9}$$
Ответ:
а) $$\frac{7}{19}$$
б) $$3\frac{4}{7}$$
в) $$2\frac{7}{11}$$
г) $$6\frac{1}{9}$$