3/14:1/28-13/21:1/28+29/42:1/28-8=(3/14-13/21+29/42):1/28-8=2/7:1/28-8=8-8=0

=0 nhé

0 nhé bạn

28/35+21/28+7/21+1/7

=4/5+3/4+1/3+1/7

=851/420

dùng máy tính là ok mà bn.

\(\frac{28}{35}+\frac{21}{28}+\frac{9}{21}+\frac{1}{7}\)

\(=(\frac{4}{5}+\frac{3}{4})+(\frac{3}{7}+\frac{1}{7})\)

\(=\frac{31}{20}+\frac{4}{7}\)

\(=2\frac{17}{140}\)

Chúc bn học tốt!!!!

\(=28\left(\dfrac{3}{14}-\dfrac{13}{21}-\dfrac{29}{42}\right)-8\\ =28\cdot\dfrac{-23}{21}-8=-\dfrac{92}{3}-8=-\dfrac{116}{3}\)

\(C=\dfrac{3}{14}:\dfrac{1}{28}-\dfrac{13}{21}:\dfrac{1}{28}-\dfrac{29}{42}:\dfrac{1}{28}-8\)

\(=28\left(\dfrac{3}{14}-\dfrac{13}{21}-\dfrac{29}{42}\right)-8\)

\(=28\left(\dfrac{9}{42}-\dfrac{26}{42}-\dfrac{29}{42}\right)-8\)

\(=28\cdot\dfrac{-46}{42}-8\)

\(=\dfrac{-116}{3}\)

c: \(\dfrac{3}{14}:\dfrac{1}{28}-\dfrac{13}{21}:\dfrac{1}{28}\)

\(=28\left(\dfrac{3}{14}-\dfrac{13}{21}\right)\)

\(=28\cdot\left(\dfrac{9}{42}-\dfrac{26}{42}\right)\)

\(=28\cdot\dfrac{-17}{42}=\dfrac{-34}{3}\)

3/14:1/28-13/21:1/28+29/42:-1/28-8

=3/14.28-13/21.28+29/42.(-28)-8

=3/14.28-13/21.28+-29/42.28-8

=(3/14-13/21+ -29/42).28-8

=-23/21.28-8

=-92/3-8=-116/3

động não tí đi

Bạn ko trả lời thì thôi bạn ấy ko biết thì mới hỏi

    \(\frac{3}{14}:\frac{1}{28}-\frac{13}{21}:\frac{1}{28}+\frac{29}{42}:\frac{1}{28}-8\)

\(=\left(\frac{3}{14}-\frac{13}{21}+\frac{29}{42}\right):\frac{1}{28}-8\)

\(=\left(\frac{9}{42}-\frac{26}{21}+\frac{29}{42}\right):\frac{1}{28}-8\)

\(=\left(\frac{-17}{42}+\frac{29}{42}\right):\frac{1}{28}-8\)

\(=\frac{12}{42}:\frac{1}{28}-8\)

\(=\frac{2}{7}.28-8\)

\(=\frac{56}{7}-8\)

\(=8-8\)

\(=0\)

\(\frac{-1}{21}+\left(\frac{-1}{28}\right)=\frac{-28}{588}+\left(\frac{-21}{588}\right)=\frac{-28-21}{588}=\frac{-49}{588}=\frac{-1}{12}\)

-1/`12

\(-\dfrac{1}{21}+\dfrac{-1}{28}=-\dfrac{1}{12}\)

Chúc bạn học tốt!!!

\(\dfrac{-1}{21}\) + \(\dfrac{-1}{28}\) = \(\dfrac{-4+\left(-3\right)}{84}\) = \(\dfrac{-7}{84}\) = \(\dfrac{-1}{12}\)