b)
[tex]( \frac{5}{2} - \frac{4}{5} + \frac{7}{15} ) \div \frac{1}{2} = ( \frac{25}{10} - \frac{8}{10} + \frac{7}{15} ) \div \frac{1}{2} = ( \frac{17}{10} + \frac{7}{15} ) \div \frac{1}{2} = ( \frac{51}{30} + \frac{14}{30} ) \div \frac{1}{2} = \frac{65}{30} \div \frac{1}{2} = \frac{13}{6} \div \frac{1}{2} = \frac{13}{6} \times \frac{2}{1} = \frac{13}{3} \times \frac{1}{1} = \frac{13}{3} = 13 \div 3 = 4.(3)[/tex]
c)
[tex] \frac{6}{7} \times ( \frac{7}{6} - \frac{3}{8} + \frac{5}{4} ) = \frac{6}{7} \times ( \frac{56}{48} - \frac{18}{48} + \frac{60}{48} ) = \frac{6}{7} \times (\frac{38}{48} + \frac{60}{48}) = \frac{6}{7} \times \frac{98}{48} = \frac{1}{1} \times \frac{14}{8} = \frac{14}{8} = \frac{7}{4} = 7 \div 4 = 1.75[/tex]
