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17 tháng 4 2017

\(A=-1,6:\left(1+\dfrac{2}{3}\right)\)

\(A=\dfrac{-16}{10}:\dfrac{5}{3}\)

\(A=\dfrac{-8}{5}.\dfrac{3}{5}\)

\(A=\dfrac{-24}{25}\)

\(B=1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)

\(B=\dfrac{14}{10}.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):\dfrac{11}{5}\)

\(B=\dfrac{14}{10}.\dfrac{15}{49}-\dfrac{22}{15}:\dfrac{11}{5}\)

\(B=\dfrac{3}{7}-\dfrac{22}{15}:\dfrac{11}{5}\)

\(B=\dfrac{3}{7}-\dfrac{2}{3}\)

\(B=\dfrac{-5}{21}\)

17 tháng 4 2017

\(A=-1,6:\left(1+\dfrac{2}{3}\right)\)
\(A=\dfrac{-8}{5}:\left(1+\dfrac{2}{3}\right)\)
\(A=\dfrac{-8}{5}:\dfrac{5}{3}\)
\(A=\dfrac{-24}{25}\)

\(B=1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
\(B=\dfrac{7}{5}.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):\dfrac{11}{5}\)
\(B=\dfrac{7}{5}.\dfrac{15}{49}-\dfrac{22}{15}:\dfrac{11}{5}\)
\(B=\dfrac{3}{7}-\dfrac{2}{3}\)
\(B=\dfrac{-5}{21}\)

A=-1/10

B câu b có và 1/5 là sao pn

14 tháng 2 2023

a) c1 := -2/-5+-5/-6+4/5

=2/5+5/6+4/5

=12/30+25/30+24/30

=61/30

c2:=(2/5+4/5)+4/5

=(2/5+4/5)+5/6

=6/5+5/6

=36/30+25/30

=61/30

b)c1:=-3/-4+11/-15+-1/2

=3/4+-11/15+-1/2

=45/60+-44/30+-30/60

-29/30

c2:=3/4+(-11/15+-1/2)

=(3/4+-1/2)+-11/15

=(3/4+-2/4)+-11/5

=1/4+-11/15

=15/60+-44/60

=-29/60

25 tháng 4 2017

A= -8/5: (1+2/3)

 = -8/5:5/3

 = -8/5.3/5

 = -24/25

B= 7/5.15/49-22/15: 11/5

 = 3/7-2/5

 = 1/35

25 tháng 4 2017

\(A=-1,6:\left(1+\frac{2}{3}\right)\)

\(A=-1,6:\frac{5}{3}\)

\(A=-\frac{24}{25}\)

\(B=1,4.\frac{15}{49}-\left(\frac{4}{5}+\frac{2}{3}\right):2\frac{1}{5}\)

\(B=\frac{135}{98}-\frac{2}{3}\)

\(B=\frac{209}{294}\)

11 tháng 5 2018

\(A=-1,6:\left(1+\frac{2}{3}\right)\)

\(A=\frac{-8}{5}:\frac{5}{3}\)

\(A=\frac{-24}{25}\)

\(B=1,4.\frac{15}{29}-\left(\frac{4}{5}+\frac{2}{3}\right):2\frac{1}{5}\)

\(B=\frac{7}{5}.\frac{15}{29}-\frac{22}{15}:\frac{11}{5}\)

\(B=\frac{21}{29}-\frac{22}{15}.\frac{5}{11}\)

\(B=\frac{21}{29}-\frac{2}{3}\)

\(B=\frac{5}{87}\)

11 tháng 5 2018

cảm ơn bn bn giải giùm mình mấy bài mình mới đăng nx ik

7 tháng 5 2019

\(\frac{2}{5}:\frac{1}{3}-\frac{2}{15}:\frac{1}{5}+\frac{3}{5}.\frac{1}{3}\)

\(=\frac{6}{5}+\frac{-2}{3}+\frac{1}{5}\)

\(=\frac{11}{15}\)

~ Hok tốt ~

7 tháng 5 2019

\(\frac{4}{2.4}+\frac{4}{4.6}+\frac{4}{6.8}+...+\frac{4}{2008.2010}\)

\(=4.\left(\frac{1}{2.4}+\frac{1}{4.6}+\frac{1}{6.8}+...+\frac{1}{2008.2010}\right)\)

\(=4.\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{2008}-\frac{1}{2010}\right)\)

\(=4.\left[\frac{1}{2}+\left(\frac{1}{4}-\frac{1}{4}\right)+\left(\frac{1}{6}-\frac{1}{6}\right)+\left(\frac{1}{8}-\frac{1}{8}\right)+...+\left(\frac{1}{2008}-\frac{1}{2008}\right)-\frac{1}{2010}\right]\)

\(=4.\left[\frac{1}{2}-\frac{1}{2010}\right]\)

\(=4.\frac{502}{1005}=\frac{2008}{1005}\)

~ Hok tốt ~

29 tháng 3 2019

Ai trả lời nhanh mình tích cho nhé!

29 tháng 3 2019

\(A=\frac{1}{1.2.3}+\frac{1}{2.3.4}+...+\frac{1}{98.99.100}\)

\(A=\frac{1}{2}.\left(\frac{2}{1.2.3}+\frac{2}{2.3.4}+...+\frac{2}{98.99.100}\right)\)

\(A=\frac{1}{2}.\left(\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+...+\frac{1}{98.99}-\frac{1}{99.100}\right)\)

\(A=\frac{1}{2}.\left(\frac{1}{2}-\frac{1}{9900}\right)\)

\(A=\frac{1}{2}.\frac{4949}{9900}\)

\(A=\frac{4949}{19800}\)

13 tháng 7 2017

\(A=\frac{16}{10}:\frac{4}{3}=\frac{16}{10}\cdot\frac{3}{4}=\frac{6}{5}\)

\(B=\frac{14}{10}\cdot\frac{15}{49}-\left(\frac{4}{5}+\frac{2}{3}\right):\frac{11}{5}\)

\(B=\frac{3}{7}-\frac{22}{15}:\frac{11}{5}\)\(=\frac{3}{7}-\frac{2}{3}\)\(=\frac{-5}{21}\)

14 tháng 7 2017

a. A= \(\frac{16}{10}:\frac{4}{3}=\frac{16}{10}.\frac{3}{4}=\frac{6}{5}\)

b. B= \(\frac{14}{10}.\frac{15}{49}-\left(\frac{4}{5}+\frac{2}{3}\right):\frac{11}{5}=\frac{3}{7}-\frac{22}{15}:\frac{11}{5}=\frac{3}{7}-\frac{2}{3}=\frac{-5}{21}\)