г) $$ \frac{c-2}{6c+4} - \frac{c-6}{15c+10} = \frac{c-2}{2(3c+2)} - \frac{c-6}{5(3c+2)} = \frac{5(c-2) - 2(c-6)}{10(3c+2)} = \frac{5c-10 - 2c + 12}{10(3c+2)} = \frac{3c+2}{10(3c+2)} = \frac{1}{10} $$
Ответ: $$ \frac{1}{10} $$