Đáp án:
Giải thích các bước giải:
$(\dfrac{-7}{15}-\dfrac{27}{10})-(\dfrac{8}{15}+\dfrac{43}{70})$
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$=\dfrac{-7}{15}-\dfrac{8}{15}-\dfrac{27}{10}-\dfrac{43}{70}$
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$=-1-\dfrac{189}{70}-\dfrac{43}{70}$
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$=-1-\dfrac{116}{35}$
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$=\dfrac{-35}{35}-\dfrac{116}{35}$
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$=\dfrac{-151}{35}$
$ $
$ $
$ $
$ $
$\dfrac{3}{7}+(\dfrac{-1}{5}+\dfrac{-3}{7})$
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$=\dfrac{3}{7}-\dfrac{1}{5}-\dfrac{3}{7}$
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$=\dfrac{-1}{5}$
$ $
$ $
$ $
$ $
$=\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}.\dfrac{9}{11}$
$ $
$=\dfrac{-5}{7}.1=\dfrac{-5}{7}$
