\(a,-\dfrac{12}{16}-\left(\dfrac{3}{4}-x\right)=-\dfrac{5}{3}\)

\(\dfrac{3}{4}-x=-\dfrac{12}{16}-\left(-\dfrac{5}{3}\right)\)

\(\dfrac{3}{4}-x=\dfrac{11}{12}\)

\(x=\dfrac{3}{4}-\dfrac{11}{12}\)

\(x=-\dfrac{1}{6}\)

\(b,x-\dfrac{3}{7}:\dfrac{9}{14}=-\dfrac{7}{3}\)

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

\(x-\dfrac{3}{7}=-\dfrac{3}{2}\)

\(x=-\dfrac{3}{2}+\dfrac{3}{7}\)

\(x=-\dfrac{15}{14}\)

\(c,-\dfrac{3}{4}x+\dfrac{5}{8}x=\dfrac{1}{3}\)

\(\left(-\dfrac{3}{4}+\dfrac{5}{8}\right)x=\dfrac{1}{3}\)

\(-\dfrac{1}{8}x=\dfrac{1}{3}\)

\(x=\dfrac{1}{3}:\left(-\dfrac{1}{8}\right)\)

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

`-12/16 - ( 3/4 - x ) = -5/3`

`=> 3/4 - x=-12/16 -(-5/3)`

`=> 3/4 - x=-12/16 +5/3`

`=> 3/4 - x=11/12`

`=> x= 3/4-11/12`

`=> x=9/12 -11/12`

`=> x=-1/6`

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`x - 3/7 : 9/14 = - 7/3`

`=>x - 3/7=-7/3 xx 9/14`

`=>x - 3/7=-3/2`

`=>x= -3/2 + 3/7`

`=>x=-15/14`

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`-3/4 x + 5/8 x =1/3`

`=> (-3/4 + 5/8) x =1/3`

`=> ( -6/8+ 5/8) x =1/3`

`=> -1/8 x=1/3`

`=>x= 1/3 : (-1/8)`

`=> x= 1/3 xx (-8)`

`=>x= -8/3`

\(\left(x-\dfrac{4}{7}\right):-\dfrac{1}{3}=1\)
\(\Rightarrow x-\dfrac{4}{7}=1\cdot-\dfrac{1}{3}\)

\(\Rightarrow x-\dfrac{4}{7}=-\dfrac{1}{3}\)

\(\Rightarrow x=-\dfrac{1}{3}+\dfrac{4}{7}\)

\(\Rightarrow x=\dfrac{5}{12}\)

___________________

\(\dfrac{2}{3}-\dfrac{7}{4}:x=\dfrac{5}{6}\)

\(\Rightarrow\dfrac{7}{4}:x=\dfrac{2}{3}-\dfrac{5}{6}\)

\(\Rightarrow\dfrac{7}{4}:x=-\dfrac{1}{6}\)

\(\Rightarrow x=\dfrac{7}{4}:-\dfrac{1}{6}\)

\(\Rightarrow x=-\dfrac{21}{2}\)

(x - 4/7) : (-1/3) = 1

x - 4/7 = -1/3

x = -1/3 +4/7

x = 5/21

--------------------

2/3 + 7/4 : x = 5/6

7/4 : x = 5/6 - 2/3

7/4 : x = 1/6

x = 7/4 : 1/6

x = 21/2

a) ( x - 4/7) : (-1/3) = 1

      x- 4/7                = 1 . (-1/3)

         x                     =-1/3 + 4/7

         x                     =   5/12

b) 2/3 + 7/4 : x = 5/6

              7/4: x  = 2/3 -5/6

                     x   = 7/4  : (-1/6 )

                     x    =    -21/2

a) 3/8 . x = 9/8 - 1

3/8 . x = 1/8

x = 1/8 : 3/8

x = 1/3

b) 4/5 . x = 7/5 - 1/5

4/5 . x = 6/5

x = 6/5 : 4/5

x = 3/2

c) 12/7 : x + 2/3 = 7/5

12/7 : x = 7/5 - 2/3

12/7 : x = 11/15

x = 12/7 : 11/15

x = 180/77

d) 3.(x + 7) - 15 = 27

3.(x + 7) = 27 + 15

3.(x + 7) = 42

x + 7 = 42 : 3

x + 7 = 14

x = 14 - 7

x = 7

a) \(\dfrac{3}{8}x=\dfrac{9}{8}-1\)

\(\Rightarrow\dfrac{3}{8}x=\dfrac{1}{8}\)

\(\Rightarrow x=\dfrac{1}{8}:\dfrac{3}{8}=\dfrac{1}{3}\)

b) \(\dfrac{4}{5}x=\dfrac{7}{5}-\dfrac{1}{5}\)

\(\Rightarrow\dfrac{4}{5}x=\dfrac{6}{5}\)

\(\Rightarrow x=\dfrac{6}{5}:\dfrac{4}{5}=\dfrac{3}{2}\)

c) \(\dfrac{12}{7}:x+\dfrac{2}{3}=\dfrac{7}{5}\)

\(\Rightarrow\dfrac{12}{7}:x=\dfrac{7}{5}-\dfrac{2}{3}\)

\(\Rightarrow\dfrac{12}{7}:x=\dfrac{11}{15}\)

\(\Rightarrow x=\dfrac{12}{7}:\dfrac{11}{15}=\dfrac{180}{77}\)

d) \(3\left(x+7\right)-15=27\)

\(\Leftrightarrow3\left(x+7\right)=42\)

\(\Leftrightarrow x+7=14\Leftrightarrow x=7\)

\(-7\left(5-x\right)-2\left(x+3\right)=12\\ \Leftrightarrow-35+7x-2x-6-12=0\\ \Leftrightarrow5x-53=0\\ \Leftrightarrow5x=53\\ \Leftrightarrow x=\dfrac{53}{5}\)

bạn đã kiểm tra kĩ chưa vậy?mình đọc đề câu B mà loạn não luôn á;-;

mik kiểm tra rùi

=> -12x + 60 + 21 - 7x = 5

=> -19x + 81 = 5

=> -19x = 5 - 81 = -76

=> 19x = 76

X = 4

khó quá ??????????????????????????????????

a) (-2) . ( x+7 ) + (-5) = 7 

<=>(-2).(x+7)=7+5

<=>x+7=12:(-2)

<=>x+7=-6

<=>x=(-6)-7

<=>x=-13

Vậy x=-13

b)(x+4) : (-7) = 14

<=>x+4=14 x (-7)

<=>x+4=-98

<=>x=-98-4

<=>x=-102

Vậy x= -102

c) 72 : ( x+5) - 4 = -12 

<=>72:(x+5)=(-12)+4

<=>x+5=72:(-8)

<=>x+5=-9

<=>x=-9-5

<=>x=-14

Vậy x= -14

d) (x+3) : (-6 ) + 12 = 8 

<=>(x+3) :(-6)=8-12

<=>x+3=(-4)x(-6)

<=>x+3=24

<=>x=24-3

<=>x=21

Vậy x= 21 

a) -12x + 60 + 21 - 7x =15

-12x - 7x + 81 = 15

-19x = 15 - 81

-19x = -66

x= -66 : (-19)

x = \(\frac{66}{19}\)

Vậy x = \(\frac{66}{19}\)

b) 30x + 60 - 6x + 30 - 24x= 100

30x - 6x - 24x + 60 +30= 100

x ( 30 - 6- 24 ) + 90 = 100

x. 0 + 90 =100

x. 0 =10 ( vô lý )

\(\Rightarrow\) x \(\in\phi\)

k đi mình lamf cho

a: =>4/3x=7/9-4/9=1/3

=>x=1/4

b: =>5/2-x=9/14:(-4/7)=-9/8

=>x=5/2+9/8=29/8

c: =>3x+3/4=8/3

=>3x=23/12

hay x=23/36

d: =>-5/6-x=7/12-4/12=3/12=1/4

=>x=-5/6-1/4=-10/12-3/12=-13/12

em moi lop 4 mà

\(d,-\dfrac{5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)

\(\Leftrightarrow-\dfrac{5}{6}-x=\dfrac{7}{12}+\dfrac{-4}{12}\)

\(\Leftrightarrow-\dfrac{5}{6}-x=\dfrac{1}{4}\)

\(\Leftrightarrow-x=-\dfrac{5}{6}-\dfrac{1}{4}\)

\(\Leftrightarrow-x=-\dfrac{13}{12}\)

\(\Leftrightarrow x=\dfrac{13}{12}\)

\(c,3x+\dfrac{3}{4}=2\dfrac{2}{3}\)

\(\Leftrightarrow3x+\dfrac{3}{4}=\dfrac{8}{3}\)

\(\Leftrightarrow3x=\dfrac{8}{3}-\dfrac{3}{4}\)

\(\Leftrightarrow3x=\dfrac{23}{12}\)

\(\Leftrightarrow x=\dfrac{23}{12}:3\)

\(\Leftrightarrow x=\dfrac{23}{36}\)