\(\Leftrightarrow\frac{3x+1}{17}+\frac{3x+1}{19}+\frac{3x+1}{23}-\frac{3x+1}{29}-\frac{3x+1}{31}=0\)

\(\Leftrightarrow\left(3x+1\right)\left(\frac{1}{17}+\frac{1}{19}+\frac{1}{23}-\frac{1}{29}-\frac{1}{31}\right)=0\)

\(\Leftrightarrow3x+1=0\) ( vì \(\frac{1}{17}+\frac{1}{19}+\frac{1}{23}-\frac{1}{29}-\frac{1}{31}\ne0\))

\(\Leftrightarrow3x=-1\)

\(\Leftrightarrow x=-\frac{1}{3}\)

\(\frac{3x+1}{17}+\frac{3x+1}{19}+\frac{3x+1}{23}=\frac{3x+1}{29}+\frac{3x+1}{31}\)

\(\Rightarrow\frac{3x+1}{17}+\frac{3x+1}{19}+\frac{3x+1}{23}-\frac{3x+1}{29}-\frac{3x+1}{31}=0\)

\(\Rightarrow\left(3x+1\right)\left(\frac{1}{17}+\frac{1}{19}+\frac{1}{23}-\frac{1}{29}-\frac{1}{31}\right)=0\)

Mà \(\frac{1}{17}+\frac{1}{19}+\frac{1}{23}-\frac{1}{29}-\frac{1}{31}\ne0\)

\(\Rightarrow3x+1=0\)

\(\Rightarrow x=-\frac{1}{3}\)

\(\frac{3x+1}{17}+\frac{3x+1}{19}+\frac{3x+1}{23}=\frac{3x+1}{29}+\frac{3x+1}{31}\)

\(\Rightarrow\frac{3x+1}{17}+\frac{3x+1}{19}+\frac{3x+1}{23}-\frac{3x+1}{29}-\frac{3x+1}{31}=0\)

\(\Rightarrow\left(3x+1\right)\left(\frac{1}{17}+\frac{1}{19}+\frac{1}{23}-\frac{1}{29}-\frac{1}{31}\right)=0\)

=>3x+1=0

=>x=-1/3

=>3x=48

hay x=16

3x-14=31

=>3x=48

=>x=16

a) 2x - 31 + 42 = - 3x - 45

2x + 11 = - 3x - 45

2x + 3x = - 45 - 11

5x = - 56

x = - 56/5

b) - 25 + 2x = 15 + 17 - x

2x + x = 32 + 25

3x = 57

x = 19

1) 3x-(4+2x)=11

    3x - 4 - 2x = 11

   3x - 2x = 11+4

     x = 15

Vậy x = 15.

2) 4x+5=11+2x

    4x - 2x = 11 - 5

    2x = 6

    x   = 6 : 2

     x  = 3

Vậy x  = 3.

3) 7x-17=31+x

    7x - x = 31  + 17

      6x = 48

        x = 48 : 6

       x  = 8

Vậy x = 8

# HOK TỐT #

\(3x-\left(4+2x\right)=11\)

\(3x-4-2x=11\)

\(x-15=0\)

\(x=15\)

\(4x+5=11+2x\)

\(2x-6=0\)

\(2x=6\)

\(x=3\)

Bn lm phần c đi , cố lên ! 

1) 3x-(4+2x)=11

    3x-4-2x=11

    3x-2x=11+4

          x=15

2) 4x+5=11+2x

    4x-2x=11-5

         2x=6

           x=6:2

           x=3

3) 7x-17=31+x

    7x-x=31+17

        6x=48

          x=48:6

          x=8

\(3x+12=36\)

\(\Leftrightarrow3x=36-12\)

\(\Leftrightarrow3x=24\)

\(\Leftrightarrow x=24\div3\)

\(\Leftrightarrow x=8\)

\(4x+28=134\)

\(\Leftrightarrow4x=134-28\)

\(\Leftrightarrow4x=106\)

\(\Leftrightarrow x=106\div4\)

\(\Leftrightarrow x=\frac{53}{2}\)

\(5x-22=-17\)

\(\Leftrightarrow5x=22-17\)

\(\Leftrightarrow5x=5\)

\(\Leftrightarrow x=5\div5\)

\(\Leftrightarrow x=1\)

3x + 12 = 36 

3x = 36 - 12

3x = 24

x = 8

4x + 28 = 134

4x = 134 - 28

4x = 106

x = 106 : 4

x = 26 , 5

5x - 22 = -17

5x = -17 + 22

5x = 5

x = 1

3x - 184 = -49

3x = -49 + 184

3x = 135

x = 135 : 3  = 45

4x + 12 = 56

4x = 56 - 12

4x = 44

x = 11

3x - 127 = - 22

3x = -22 + 127 

3x = 105

x = 105 : 3 = 35

3x + 22 = 124

3x = 124 - 22 = 102

x = 102 : 3

x = 34

4x - 9 = 31

4x = 31 + 9 = 40

x = 40 : 4= 10

5x - 211 = -31 

5x = -31 + 211

5x = 180

x = 180 : 5

x  = 36

2) 3x + 12 = 36

    3x         =36-12

    3x         =24

     x          =24 :3

      x          =8

\(\left|x-11\right|=7\)

\(\Leftrightarrow\orbr{\begin{cases}x-11=7\\x-11=-7\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=18\\x=4\end{cases}}\)

d,\(\left(3x-12\right)\left(x+31\right)=0\)

\(\Rightarrow\orbr{\begin{cases}3x-12=0\\x+31=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=4\\x=-31\end{cases}}\)

=\(\dfrac{11}{31}\)*\(\left(\dfrac{-2}{17}-\dfrac{-9}{17}\right)\)+\(\dfrac{7}{31}\)*\(\dfrac{-20}{17}\)

=\(\dfrac{11}{31}\)*\(\dfrac{-7}{17}\)+\(\dfrac{7}{31}\)*\(\dfrac{-20}{17}\)

=\(\dfrac{-77}{512}\)+\(\dfrac{-140}{512}\)

=\(\dfrac{-217}{512}\)

nhanh giúp mk với

\(=\dfrac{6}{119}\)

\(\dfrac{13}{17}-\dfrac{23}{31}+\dfrac{4}{17}-\dfrac{8}{31}\)

\(=\left(\dfrac{13}{17}+\dfrac{4}{17}\right)-\left(\dfrac{23}{31}+\dfrac{8}{31}\right)\)

\(=\dfrac{17}{17}-\dfrac{31}{31}\)

\(=1-1\)

\(=0\)

13/17 - 23/31 + 4/17- 8/31

= (13/17 + 4/17) - (23/31 - 8/31)

= 1 - 15/31

= 16/31