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27 tháng 9

Bài 1:

a; \(\dfrac{7}{8}\) + \(x\) = \(\dfrac{4}{7}\)

     \(x\) = \(\dfrac{4}{7}\) - \(\dfrac{7}{8}\)

     \(x\) = \(\dfrac{32}{56}\) - \(\dfrac{49}{56}\)

     \(x=-\) \(\dfrac{49}{56}\)

Vậy \(x=-\dfrac{49}{56}\)

b; 6 - \(x\) = - \(\dfrac{3}{4}\)

         \(x\) = 6 + \(\dfrac{3}{4}\)

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

         \(x=\dfrac{27}{4}\)

Vậy \(x=\dfrac{27}{4}\) 

c; \(\dfrac{1}{-5}\) + \(x\) = \(\dfrac{3}{4}\)

              \(x\) = \(\dfrac{3}{4}\) + \(\dfrac{1}{5}\)

              \(x=\dfrac{15}{20}\) + \(\dfrac{4}{20}\)

               \(x=\dfrac{19}{20}\)

Vậy \(x=\dfrac{19}{20}\) 

27 tháng 9

      Bài 1:

d; - 6 - \(x\) = - \(\dfrac{3}{5}\)

      \(x\)   = - 6 + \(\dfrac{3}{5}\)

       \(x=-\dfrac{30}{5}\) + \(\dfrac{3}{5}\)

       \(x=-\dfrac{27}{5}\)

Vậy \(x=-\dfrac{27}{5}\)

e; - \(\dfrac{2}{6}\) + \(x\) = \(\dfrac{5}{7}\)

             \(x\) = \(\dfrac{5}{7}\) + \(\dfrac{2}{6}\)

             \(x\) = \(\dfrac{15}{21}\) + \(\dfrac{1}{3}\)

              \(x=\dfrac{15}{21}\) + \(\dfrac{7}{21}\)

               \(x=\dfrac{22}{21}\)

Vậy \(x=\dfrac{22}{21}\) 

f; - 8 - \(x\) =  - \(\dfrac{5}{3}\)

          \(x\) = \(-\dfrac{5}{3}\) + 8

         \(x\) = \(\dfrac{-5}{3}\) + \(\dfrac{24}{3}\)

         \(x\) = \(\dfrac{-19}{3}\)

Vậy \(x=-\dfrac{19}{3}\) 

 

            

 

18 tháng 9 2020

\(x-\frac{3}{8}=\frac{1}{6}-\frac{1}{5}\)

=> \(x-\frac{3}{8}=\frac{5}{30}-\frac{6}{30}=-\frac{1}{30}\)

=> \(x=-\frac{1}{30}+\frac{3}{8}\)

=> \(x=\frac{41}{120}\)

\(-\frac{7}{10}\left(x+\frac{1}{3}\right)=\frac{4}{5}\)

=> \(-\frac{7}{10}x-\frac{7}{30}=\frac{4}{5}\)

=> \(-\frac{7}{10}x=\frac{4}{5}+\frac{7}{30}=\frac{31}{30}\)

=> \(x=\frac{31}{30}:\left(-\frac{7}{10}\right)=\frac{31}{30}\cdot\left(-\frac{10}{7}\right)=-\frac{31}{21}\)

\(x-\frac{4}{3}=\frac{5}{6}\Rightarrow x=\frac{5}{6}+\frac{4}{3}=\frac{5}{6}+\frac{8}{6}=\frac{13}{6}\)

Thiếu đề 

\(\frac{6}{5}+\left(x-\frac{2}{3}\right)=\frac{4}{7}\)

=> \(\frac{6}{5}+x-\frac{2}{3}=\frac{4}{7}\)

=> \(\frac{6}{5}+x=\frac{4}{7}+\frac{2}{3}=\frac{26}{21}\)

=> \(x=\frac{26}{21}-\frac{6}{5}=\frac{4}{105}\)

Bài 1: 

a) Ta có: \(\dfrac{17}{6}-x\left(x-\dfrac{7}{6}\right)=\dfrac{7}{4}\)

\(\Leftrightarrow\dfrac{17}{6}-x^2+\dfrac{7}{6}x-\dfrac{7}{4}=0\)

\(\Leftrightarrow-x^2+\dfrac{7}{6}x+\dfrac{13}{12}=0\)

\(\Leftrightarrow-12x^2+14x+13=0\)

\(\Delta=14^2-4\cdot\left(-12\right)\cdot13=196+624=820\)

Vì Δ>0 nên phương trình có hai nghiệm phân biệt là:

\(\left\{{}\begin{matrix}x_1=\dfrac{14-2\sqrt{205}}{-24}=\dfrac{-7+\sqrt{205}}{12}\\x_2=\dfrac{14+2\sqrt{2015}}{-24}=\dfrac{-7-\sqrt{205}}{12}\end{matrix}\right.\)

b) Ta có: \(\dfrac{3}{35}-\left(\dfrac{3}{5}-x\right)=\dfrac{2}{7}\)

\(\Leftrightarrow\dfrac{3}{5}-x=\dfrac{3}{35}-\dfrac{10}{35}=\dfrac{-7}{35}=\dfrac{-1}{5}\)

hay \(x=\dfrac{3}{5}-\dfrac{-1}{5}=\dfrac{3}{5}+\dfrac{1}{5}=\dfrac{4}{5}\)

12 tháng 7 2021

ai giúp mik vs

1 tháng 10 2023

\(\dfrac{5}{7}\cdot\dfrac{6}{11}+\dfrac{5}{11}\cdot\dfrac{1}{7}-\dfrac{5}{7}\cdot\dfrac{14}{11}\)

\(=\dfrac{5}{7}\cdot\dfrac{6}{11}+\dfrac{5}{7}\cdot\dfrac{1}{11}-\dfrac{5}{7}\cdot\dfrac{14}{11}\)

\(=\dfrac{5}{7}\cdot\left(\dfrac{6}{11}+\dfrac{1}{11}-\dfrac{14}{11}\right)\)

\(=\dfrac{5}{7}\cdot\dfrac{-7}{11}=\dfrac{-5}{11}\)

12 tháng 4 2018

E = x^(4)*y^(4)+x^(5)*y^(5)+x^(6)*y^(6)+x^(7)*y^(7)+x^(8)*y^(8)+x^(9)*y^(9)+x^(10)*y^(10) tại x=-1, y=1 nha

1: x=3/4-1/2=3/4-2/4=1/4

2: x-1/5=2/11

=>x=2/11+1/5=21/55

3: x-5/6=16/42-8/56

=>x-5/6=8/21-4/28=5/21

=>x=5/21+5/6=15/14

4: x/5=5/6-19/30

=>x/5=25/30-19/30=6/30=1/5

=>x=1

5: =>|x|=1/3+1/4=7/12

=>x=7/12 hoặc x=-7/12

6: x=-1/2+3/4

=>x=3/4-1/2=1/4

11: x-(-6/12)=9/48

=>x+1/2=3/16

=>x=3/16-1/2=-5/16

21 tháng 7 2023

1)x= 1/4

2)x= 2/11+ 1/5

   x= 21/55

3)x - 5/6 = 5/21

   x         = 5/21+5/6

   x         = 15/14

4)x/5 = 5/6 + -19/30

   x:5 = 1/5

   x    = 1/5.5

   x    = 1

5) |x| - 1/4 = 6/18

    |x|           = 6/18 - 1/4

    |x|            =7/12

⇒x= 7/12 hoặc -7/12

6)x = -1/2 +3/4

   x= 1/4

7) x/15 = 3/5 + -2/3

   x:15  = -1/15

  x        = -1/15. 15

  x        = -1

8)11/8 + 13/6 = 85/x  

       85/24      = 85/x

  ⇒      x           = 24

9) x - 7/8 = 13/12

   x          = 13/12 + 7/8

   x          = 47/24

10)x - -6/15 = 4/27  

     x            = 4/27 + (-6/15)

    x             = -34/135

11) -(-6/12)+x = 9/48

                    x= 9/48 - 6/12

                    x = -5/16

12) x - 4/6 = 5/25 + -7/15

      x -4/6  =  -4/15

     x           = -4/15 + 4/6

    x             = 2/5

`#3107.101107`

\(\dfrac{5}{7}\times\dfrac{6}{11}+\dfrac{5}{11}\times\dfrac{1}{7}-\dfrac{5}{7}\times\dfrac{14}{11}\\ =\dfrac{5}{7}\times\dfrac{6}{11}+\dfrac{5}{7}\times\dfrac{1}{11}-\dfrac{5}{7}\times\dfrac{14}{11}\\ =\dfrac{5}{7}\times\left(\dfrac{6}{11}+\dfrac{1}{11}-\dfrac{14}{11}\right)\\ =\dfrac{5}{7}\times\left(-\dfrac{7}{11}\right)\\ =-\dfrac{5}{11}\)

28 tháng 6 2017

c) \(\left(3x-1\right).\left(2x+7\right)-\left(x+1\right).\left(6x-5\right)=\left(x+2\right)-\left(x-5\right)\)

\(\Leftrightarrow6x^2+21x-2x-7-\left(6x^2-5x+6x-5\right)=x+2-x+5\)

\(\Leftrightarrow18x-2-7=0\)

\(\Rightarrow x=\dfrac{9}{18}=\dfrac{1}{2}\)

28 tháng 6 2017

b) \(2.\left(3x-1\right).\left(2x+5\right)-6.\left(2x-1\right).\left(x+2\right)=1\)

\(\Leftrightarrow\left(6x-2\right).\left(2x+5\right)-\left(12x-6\right).\left(x+2\right)=1\)

\(\Leftrightarrow12x^2+30x-4x-10-\left(12x^2+24x-6x-12\right)=1\)

\(\Leftrightarrow12x^2+26x-10-12x^2-18x +12=1\)

\(\Leftrightarrow8x+2=1\)

\(\Rightarrow x=\dfrac{-1}{8}\)