[tex]a) \\ \\ a = - \frac{3}{4} - ( - \frac{2}{3}) - ( + \frac{5}{6}) = - \frac{3}{4} + \frac{2}{3} - \frac{5}{6} = \frac{ - 9 + 8 - 10}{12} = \frac{ - 11}{12} = - \frac{11}{12} [/tex]
[tex]b = - \frac{5}{12} - ( - \frac{7}{18}) - ( + \frac{1}{4}) = - \frac{5}{12} + \frac{7}{18} - \frac{1}{4} = \frac{ - 15 + 14 - 9}{36} = \frac{ - 10}{36} = - \frac{10}{36} = - \frac{5}{18} [/tex]
[tex]c = ( - 1 \frac{1}{2}) - ( - 2 \frac{1}{4}) - ( + 1 \frac{1}{6}) = ( - \frac{1}{2}) - ( - \frac{1}{2}) - \frac{1}{6} = - \frac{1}{6} [/tex]
[tex]b) \\ \\ a = ( - \frac{3}{8}) - ( + \frac{1}{4}) - ( + \frac{5}{6}) = - ( \frac{3}{8} + \frac{1}{4} + \frac{5}{6}) = - ( \frac{3 \times 3}{8 \times 3} + \frac{1 \times 6}{4 \times 6} + \frac{5 \times 4}{6 \times 4}) = - ( \frac{9}{24} + \frac{6}{24} + \frac{20}{24}) = - \frac{9 + 6 + 20}{24} = - \frac{35}{24} [/tex]
[tex]b = - \frac{5}{6} - ( + \frac{1}{12}) - ( - \frac{11}{18}) = - \frac{5}{6} - \frac{1}{12} + \frac{11}{18} = \frac{ - 30 - 3 + 22}{36} = \frac{ - 11}{36} = - \frac{11}{36} [/tex]
[tex]c = - \frac{4}{3} - ( - \frac{13}{12}) - ( + \frac{4}{9}) = - \frac{4}{3} + \frac{13}{12} - \frac{4}{9} = \frac{ - 48 + 39 - 16}{36} = \frac{ - 25}{36} = - \frac{25}{36} [/tex]
