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25 tháng 7 2017

giao cho mik

a)346.124 - 7.(2x - 1 ) = 346

      42904 - 7.(2x - 1 ) = 346

                  7.(2x - 1 ) = 42904 - 346

                  7.(2x - 1 ) = 42558

                        2x - 1 = 42558 :7

                        2x - 1 = 42558/7

                             2x = 42558/7+1 

                             2x = 42565/7

                               x = 42565/7:2

                               x = 42565/14

25 tháng 7 2017

a)346.124 - 7.(2x - 1 ) = 346

      42904 - 7.(2x - 1 ) = 346

                  7.(2x - 1 ) = 42904 - 346

                  7.(2x - 1 ) = 42558

                        2x - 1 = 42558 :7

                        2x - 1 = 42558/7

                             2x = 42558/7+1 

                             2x = 42565/7

                               x = 42565/7:2

                               x = 42565/14

a:\(\Leftrightarrow7\left(2x-1\right)=346\cdot124-346=42558\)

=>2x-1=42558/7

=>2x=42565/7

hay x=42565/14

b: \(\Leftrightarrow2\left(7x+5\right)=23-\dfrac{4}{3}=\dfrac{65}{3}\)

=>7x+5=65/6

=>7x=35/6

hay x=5/6

22 tháng 7 2017

a) 7(2x-1)=(346.124)-346

14x-7=42558

14x=42551

x=42551/14

b) 4/3+2(5+7x)=23

2(5+7x)=65/3

5+7x=65/6

7x=35/6

x=5/6

22 tháng 7 2017

a) 346.124-7.(2x-1)=343

346.124-14x+7=343

42904-14x+7=343

-14x=343-42904-7

-14x=-42568

x=\(\dfrac{-42568}{-14}\)=\(\dfrac{42568}{14}\)=3,04

vậy x = 3,04

b)\(\dfrac{4}{3}\)+2(5+7x)=115:5

\(\dfrac{4}{3}\)+10+14x=23

14x=23-10-\(\dfrac{4}{3}\)

14x= \(\dfrac{35}{3}\)

x=\(\dfrac{35}{3}\):14

x=\(\dfrac{35}{42}\)=\(\dfrac{5}{6}\)

25 tháng 7 2017

Tìm x :

346 . 124 - 7 . ( 2x - 1 ) = 346

7 . ( 2x - 1 ) = ( 346 . 124 ) - 346

7. ( 2x - 1 ) = 346 . 123

7 . 2x - 7 .1 = 42558

7 . 2x = 42558 - 7

7.2. x = 42551

14 . x = 42551

=> x = \(\dfrac{42551}{14}\)
Vậy : x = \(\dfrac{42551}{14}\)

b) \(\dfrac{4}{3}\) +2 . ( 5 + 7x ) = 115 : 5

\(\dfrac{4}{3}\) + 2. 5 + 2 . 7.x = 23

\(\dfrac{4}{3}\) + 10 + 14 . x = 23

\(\dfrac{4}{3}\) + 24 . x = 23

=> \(\dfrac{76}{3}\) . x = 23

=> x = 23 : \(\dfrac{76}{3}\)

=> x = \(\dfrac{69}{76}\)

Vậy x = \(\dfrac{69}{76}\)

26 tháng 2 2022

a, \(\dfrac{4x}{7}=\dfrac{1}{5}+\dfrac{2}{3}=\dfrac{3+10}{15}=\dfrac{13}{15}\Rightarrow60x=91\Leftrightarrow x=\dfrac{91}{60}\)

b, \(\dfrac{5}{7}:x=\dfrac{1}{6}+\dfrac{4}{5}=\dfrac{5+24}{30}=\dfrac{29}{30}\Leftrightarrow x=\dfrac{5}{7}:\dfrac{29}{30}=\dfrac{150}{203}\)

a: =>x/27+1=-2/3

=>x/27=-5/3

=>x=-45

b: \(\Leftrightarrow x-4=\dfrac{2}{5}:\dfrac{20}{21}=\dfrac{2}{5}\cdot\dfrac{21}{20}=\dfrac{42}{100}=\dfrac{21}{50}\)

=>x=221/50

c: \(\Leftrightarrow x+\dfrac{2}{3}=\dfrac{4}{60}=\dfrac{1}{15}\)

=>x=1/15-2/3=1/15-10/15=-9/15=-3/5

d: \(\Leftrightarrow x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{15}{14}\cdot\dfrac{21}{20}\)

=>\(x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{3}{2}\cdot\dfrac{3}{4}=\dfrac{1}{5}-\dfrac{9}{8}=\dfrac{-37}{40}\)

=>x=-37/24

e: =>-3/7x=84/45

=>x=-196/45

f: =>11/10x=-2/3

=>x=-20/33

24 tháng 7 2018

Giải:

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

\(\Leftrightarrow2x=\frac{1}{2}-\left(\frac{1}{5}-\frac{2}{3}\right)\)

\(\Leftrightarrow2x=\frac{1}{2}-\frac{-7}{15}\)

\(\Leftrightarrow2x=\frac{11}{15}\)

\(\Leftrightarrow x=\frac{11}{15}:2\)

\(\Leftrightarrow x=\frac{11}{30}\)

b) \(4\left(\frac{1}{3}-3\right)+\frac{1}{2}=\frac{5}{6}+x\)

\(\Leftrightarrow\frac{-61}{6}=\frac{5}{6}+x\)

\(\Leftrightarrow x=\frac{-61}{6}-\frac{5}{6}\)

\(\Leftrightarrow x=\frac{-66}{6}=-11\)

21 tháng 7 2018

a) ( 2x - 3 ) - ( x - 5 ) = ( x + 7 ) - ( x + 2 ) 

<=> 2x - 3 - x + 5 = x + 7 - x - 2

<=> x = 3

b)(7x-5)-(6x+4)=(2x+3)-(2x+1)

<=> 7x - 5 - 6x - 4 = 2x + 3 - 2x - 1

<=> x = 11

c)(9x-3)-(8x+5)=(3x+2)

<=> 9x - 3 - 8x - 5 = 3x + 2

<=> -2x = 10

<=> x = -5

d)(x+7)-(2x+3)=(3x+5)-(2x+4)

<=> x + 7 - 2x - 3 = 3x + 5 - 2x - 4

<=> -2x = -3

<=> x = 3/2

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b: \(\dfrac{5}{7}-\dfrac{2}{3}\cdot x=\dfrac{4}{5}\)

=>\(\dfrac{2}{3}x=\dfrac{5}{7}-\dfrac{4}{5}=\dfrac{25-28}{35}=\dfrac{-3}{35}\)

=>\(x=-\dfrac{3}{35}:\dfrac{2}{3}=\dfrac{-3}{35}\cdot\dfrac{3}{2}=-\dfrac{9}{70}\)
c: \(\dfrac{1}{2}x+\dfrac{3}{5}x=-\dfrac{2}{3}\)

=>\(x\left(\dfrac{1}{2}+\dfrac{3}{5}\right)=-\dfrac{2}{3}\)

=>\(x\cdot\dfrac{5+6}{10}=\dfrac{-2}{3}\)

=>\(x\cdot\dfrac{11}{10}=-\dfrac{2}{3}\)

=>\(x=-\dfrac{2}{3}:\dfrac{11}{10}=-\dfrac{2}{3}\cdot\dfrac{10}{11}=\dfrac{-20}{33}\)

d: \(\dfrac{4}{7}\cdot x-x=-\dfrac{9}{14}\)

=>\(\dfrac{-3}{7}\cdot x=\dfrac{-9}{14}\)

=>\(\dfrac{3}{7}\cdot x=\dfrac{9}{14}\)

=>\(x=\dfrac{9}{14}:\dfrac{3}{7}=\dfrac{9}{14}\cdot\dfrac{7}{3}=\dfrac{3}{2}\)