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11 tháng 4 2018

2,

\(M=\dfrac{\dfrac{3}{5}+\dfrac{3}{7}-\dfrac{3}{11}}{\dfrac{4}{5}+\dfrac{4}{7}-\dfrac{4}{11}}\) =\(\dfrac{3\left(\dfrac{1}{5}+\dfrac{1}{7}-\dfrac{1}{11}\right)}{4\left(\dfrac{1}{5}+\dfrac{1}{7}-\dfrac{1}{11}\right)}\)

\(=\dfrac{3}{4}\)

3 tháng 8 2016

\(\left(\frac{-1}{2}\right)^3:\frac{11}{8}-25\%.\left(\frac{-68}{11}\right)\)

\(=\frac{-1}{8}.\frac{8}{11}-\frac{1}{4}.\left(\frac{-68}{11}\right)\)

\(=\frac{-1}{11}-\frac{-17}{11}\)

\(=\frac{16}{11}\)

1 tháng 5 2021

-3/11.(-22)/66.121/15

=(-3).(-22).121

 11.66.15

=11

15

3/7.2/5.7/3.20.19/72

=3.2.7.20.19

7.5.3.72

=76

16

6/7.8/13+6/13.9/7-3/13.6/7

=6/7.8/13+6/7.9/13-3/13.6/7

=6/7.(8/13+9/13-3/13)

=6/7.14/13

=12/13

-1/4.152/11+68/4.(-1)/11

=152/4.(-1)/11+68/4.(-1)/11

=(-1)/11.(152/4+68/4)

=(-1)/11.220/4

=-110/22

-5/7.2/11+(-5)/7.9/11+12/7

=-5/7.2/11+-5/7.9/11+12/7

=-5/7.(2/11+9/11)+12/7

=-5/7.1+12/7

=(-5)/7+12/7

=7/7

=1

146/13-(18/7+68/13)

=146/13-18/7-68/13

=(146/13-68/13)-18/7

=78/13-18/7

=6-18/7

=42/7-18/7

=24/7

a: \(M=-\dfrac{152}{44}+\dfrac{-68}{44}=\dfrac{-220}{44}=-5\)

b: \(N=\dfrac{-9\cdot53}{25\cdot3}+\dfrac{27}{125}\cdot\dfrac{22}{3}=\dfrac{-1791}{375}\)

dễ mà em đổi hỗn số ra rùi nhóm chúng lại!!

547567567868768979780897089098798

\(\frac{-1}{4}.\frac{152}{11}-0,25:\frac{68}{11}\)

\(\left[\frac{-1}{4}.0,25\right]-\frac{152}{11}:\frac{68}{11}\)

\(\frac{-1}{16}-\frac{38}{17}\)

=...........................

mk ko chắc!!

56457657568768797890808945576

\(\frac{1}{5.8}+\frac{1}{8.11}+\frac{1}{11.14}+....+\frac{1}{197.200}\)

\(=\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+....+\frac{1}{197}-\frac{1}{200}\)

\(=\frac{1}{5}-\frac{1}{200}\)

\(=\frac{40}{200}-\frac{1}{200}\)

\(=\frac{39}{200}\)

#H

10 tháng 7 2021

Trả lời:

\(\frac{1}{5.8}+\frac{1}{8.11}+\frac{1}{11.14}+...+\frac{1}{197.200}\)

\(=\frac{1.3}{5.8.3}+\frac{1.3}{8.11.3}+\frac{1.3}{11.14.3}+...+\frac{1.3}{197.200.3}\)

\(=\frac{1}{3}.\left(\frac{3}{5.8}+\frac{3}{8.11}+\frac{3}{11.14}+...+\frac{3}{197.200}\right)\)

\(=\frac{1}{3}.\left(\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+...+\frac{1}{197}-\frac{1}{200}\right)\)

\(=\frac{1}{3}.\left(\frac{1}{5}-\frac{1}{200}\right)=\frac{1}{3}.\frac{39}{200}=\frac{13}{200}\)