a)(-7/15-27/10)-(8/15+43/70) b)3/7+(-1/5+-3/7) c)-5/7.2/11+-5/7.9/11

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1. a) $(\dfrac{-7}{15} – \dfrac{27}{10} ) – (\dfrac{8}{15} + \dfrac{43}{70})$

   $ = \dfrac{-7}{15} – \dfrac{27}{10} – \dfrac{8}{15} – \dfrac{43}{70}$

   $ = ( \dfrac{-7}{15} – \dfrac{8}{15} ) – ( \dfrac{189}{70} + \dfrac{43}{70})$

   $ = -1 – \dfrac{116}{35}  = \dfrac{-151}{35}$

   b) $\dfrac{3}{7} + (\dfrac{-1}{5} + \dfrac{-3}{7} )$

   $ = \dfrac{3}{7} – \dfrac{3}{7} + \dfrac{-1}{5}$

   $ =\dfrac{-1}{5}$

   c) $\dfrac{-5}{7} . \dfrac{2}{11} + \dfrac{-5}{7}. \dfrac{9}{11}$

   $ = \dfrac{-5}{7}.  ( \dfrac{2}{11} + \dfrac{9}{11})$

   $ = \dfrac{-5}{7}. 1 = \dfrac{-5}{7}$

     

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