bài 1: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 20/10/2021 Bởi Serenity bài 1: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
Đáp án: Giải thích các bước giải: $(\dfrac{-7}{15}-\dfrac{27}{10})-(\dfrac{8}{15}+\dfrac{43}{70})$ $ $ $=\dfrac{-7}{15}-\dfrac{8}{15}-\dfrac{27}{10}-\dfrac{43}{70}$ $ $ $=-1-\dfrac{189}{70}-\dfrac{43}{70}$ $ $ $=-1-\dfrac{116}{35}$ $ $ $=\dfrac{-35}{35}-\dfrac{116}{35}$ $ $ $=\dfrac{-151}{35}$ $ $ $ $ $ $ $ $ $\dfrac{3}{7}+(\dfrac{-1}{5}+\dfrac{-3}{7})$ $ $ $=\dfrac{3}{7}-\dfrac{1}{5}-\dfrac{3}{7}$ $ $ $=\dfrac{-1}{5}$ $ $ $ $ $ $ $ $ $=\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}.\dfrac{9}{11}$ $ $ $=\dfrac{-5}{7}.1=\dfrac{-5}{7}$ Bình luận
Đáp án:
Giải thích các bước giải:
$(\dfrac{-7}{15}-\dfrac{27}{10})-(\dfrac{8}{15}+\dfrac{43}{70})$
$ $
$=\dfrac{-7}{15}-\dfrac{8}{15}-\dfrac{27}{10}-\dfrac{43}{70}$
$ $
$=-1-\dfrac{189}{70}-\dfrac{43}{70}$
$ $
$=-1-\dfrac{116}{35}$
$ $
$=\dfrac{-35}{35}-\dfrac{116}{35}$
$ $
$=\dfrac{-151}{35}$
$ $
$ $
$ $
$ $
$\dfrac{3}{7}+(\dfrac{-1}{5}+\dfrac{-3}{7})$
$ $
$=\dfrac{3}{7}-\dfrac{1}{5}-\dfrac{3}{7}$
$ $
$=\dfrac{-1}{5}$
$ $
$ $
$ $
$ $
$=\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}.\dfrac{9}{11}$
$ $
$=\dfrac{-5}{7}.1=\dfrac{-5}{7}$
a)(-7/15-27/10)-(8/15+43/70)=-151/35
b)3/7+(-1/5+-3/7)=-1/5
c)-5/7.2/11+-5/7.9/11=-5/7