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23 tháng 7 2020

\(x+3,5-\frac{4}{7}=\frac{3}{2}-5\frac{1}{8}\)

=> \(x+\frac{35}{10}-\frac{4}{7}=\frac{3}{2}-\frac{41}{8}\)

=> \(x+\frac{7}{2}-\frac{4}{7}=\frac{12}{8}-\frac{41}{8}\)

=> \(x+\frac{7}{2}-\frac{4}{7}=-\frac{29}{8}\)

=> \(x+\frac{7}{2}=-\frac{29}{8}+\frac{4}{7}=-\frac{171}{56}\)

=> \(x=-\frac{171}{56}-\frac{7}{2}=-\frac{367}{56}\)

23 tháng 7 2020

Trả lời:

\(x+3,5-\frac{4}{7}=\frac{3}{2}-5\frac{1}{8}\)

\(\Leftrightarrow x+\frac{7}{2}-\frac{4}{7}=\frac{3}{2}-\frac{41}{8}\)

\(\Leftrightarrow x+\frac{7}{2}-\frac{4}{7}=\frac{-29}{8}\)

\(\Leftrightarrow x+\frac{7}{2}=\frac{-171}{56}\)

\(\Leftrightarrow x=\frac{-367}{56}\)

Vậy \(x=\frac{-367}{56}\)

27 tháng 4 2019

Bài 2 :

1) \(x-70=-45\) 2) \(\frac{4}{7}:x=\frac{12}{28}\)

\(\Rightarrow\) \(x=-45+70\) \(\Rightarrow x=\frac{4}{7}:\frac{12}{28}\)

\(\Rightarrow\) \(x=25\) \(\Rightarrow x=\frac{4}{3}\)

Vậy \(x=25\) Vậy \(x=\frac{4}{3}\)

3) Giống câu c) ở bài 1

4) \(x-50=-35\) 5) \(\frac{4}{7}.x=\frac{11}{18}\)

\(\Rightarrow x=-35+50\) \(\Rightarrow x=\frac{11}{28}:\frac{4}{7}\)

\(\Rightarrow x=15\) \(\Rightarrow x=\frac{77}{72}\)

Vậy \(x=15\) Vậy \(x=\frac{77}{72}\)

6) \(\left(\frac{2}{3}x+2,5\right):2\frac{2}{6}=6\)

\(\Rightarrow\)\(\left(\frac{2}{3}x+2,5\right):\frac{14}{6}=6\)

\(\Rightarrow\) \(\frac{2}{3}x+2,5=6.\frac{14}{6}\)

\(\Rightarrow\frac{2}{3}x+2,5=14\)

\(\Rightarrow\frac{2}{3}x=\frac{23}{2}\)

\(\Rightarrow x=\frac{23}{2}:\frac{2}{3}\)

\(\Rightarrow x=\frac{69}{4}\)

Vậy \(x=\frac{69}{4}\)

27 tháng 4 2019

Bài 1:

1) \(\frac{7}{5}+\frac{-8}{5}=-\frac{1}{5}\)

2) \(-\frac{6}{5}.\frac{15}{24}=-\frac{3}{4}\)

3) \(\left(\frac{2}{3}+1,5\right)-3,5:7\frac{1}{2}=\)\(\frac{13}{6}-\frac{7}{15}=\frac{17}{10}\)

4) \(\frac{5}{8}-\frac{-7}{9}=\frac{5}{8}+\frac{7}{9}=\frac{101}{72}\)

5)\(\frac{-7}{3}.\frac{12}{28}=-1\)

HQ
Hà Quang Minh
Giáo viên
7 tháng 10 2023

 a) \(1\frac{2}{7} = 1 + \frac{2}{7} = \frac{9}{2}\)

\(\begin{array}{l}x:1\frac{2}{7} =  - 3,5\\x:\frac{9}{7} =  - \frac{7}{2}\\x =  - \frac{7}{2}.\frac{9}{7}\\x =  - \frac{9}{2}\end{array}\)

b) \(0,4.x - \frac{1}{5}.x = \frac{3}{4}\)

\(\begin{array}{l}\frac{2}{5}.x - \frac{1}{5}.x = \frac{3}{4}\\\left( {\frac{2}{5} - \frac{1}{5}} \right).x = \frac{3}{4}\\\frac{1}{5}.x = \frac{3}{4}\\x = \frac{3}{4}:\frac{1}{5}\\x = \frac{3}{4}.5\\x = \frac{{15}}{4}\end{array}\)

15 tháng 6 2017

\(x+3,5-\frac{4}{7}=\frac{3}{2}-5\frac{1}{8}\)

\(x+3,5-\frac{4}{7}=-\frac{29}{8}\)

\(x+3,5=-\frac{29}{8}+\frac{4}{7}\)

\(x+3,5=-\frac{117}{56}\)

      \(\Leftrightarrow x=-\frac{367}{56}\)

4 tháng 5 2019

1. 0,4x - 1/5x = 3/4

=> 1/5x = 3/4

=> x = 3/4 : 1/5

=> x = 15/4

4 tháng 5 2019

2.

x : 1 2/7 = -3,5

=> x = -3,5 . 9/7 

=> x = -9/2

30 tháng 4 2019

\(\left(\frac{3}{8}+-\frac{3}{4}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)

\(=\left(\frac{9}{24}+-\frac{18}{24}+\frac{14}{24}\right):\frac{5}{6}+\frac{1}{2}\)

\(=\frac{5}{24}:\frac{5}{6}+\frac{1}{2}\)

\(=\frac{5}{24}.\frac{6}{5}+\frac{1}{2}\)

\(=\frac{1}{4}+\frac{1}{2}\)

\(=\frac{1}{4}+\frac{2}{4}\)

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

30 tháng 4 2019

\(\frac{1}{2}+\frac{3}{4}-\left(\frac{3}{4}-\frac{4}{5}\right)\)

\(=\frac{1}{2}+\frac{3}{4}-\left(\frac{15}{20}-\frac{16}{20}\right)\)

\(=\frac{1}{2}+\frac{3}{4}-\frac{-1}{20}\)

\(=\frac{10}{20}+\frac{15}{20}-\frac{-1}{20}\)

\(=\frac{25}{20}-\frac{-1}{20}\)

\(=\frac{26}{20}\)

\(=\frac{13}{10}\)

16 tháng 7 2017

\(a.-1,52+\frac{2}{47}-x=3.\)

\(\Leftrightarrow\frac{2}{47}-x=4,52\)

\(\Leftrightarrow x=\frac{2}{47}-4,52\)

\(\Leftrightarrow x=-\frac{5261}{1175}\)

\(b.x+3,5-\frac{4}{7}=\frac{3}{2}-1\frac{3}{5}\)

\(\Leftrightarrow x=\frac{3}{2}-\frac{8}{5}-\frac{7}{2}+\frac{4}{7}\)

\(\Leftrightarrow x=-\frac{106}{35}\)

\(c.\left(x:2\frac{1}{8}\right).\frac{1}{6}=-\frac{3}{8}.\left(\frac{1}{2}-1\frac{3}{5}\right)\)

\(\Leftrightarrow\left(x:\frac{17}{8}\right).\frac{1}{6}=-\frac{3}{16}+\frac{3}{5}\)

\(\Leftrightarrow\left(x:\frac{17}{8}\right).\frac{1}{6}=\frac{33}{80}\)

\(\Leftrightarrow x:\frac{17}{8}=\frac{99}{40}\)

\(\Leftrightarrow x=\frac{99}{40}.\frac{17}{8}\)

\(\Leftrightarrow x=\frac{1683}{320}\)