a: \(x-43=\left(35-x\right)-48\)

=>\(x-43=35-x-48\)

=>\(x-43=-x-13\)

=>\(x+x=-13+43\)

=>2x=30

=>x=30/2=15

b: \(305-x+14=48+\left(x-23\right)\)

=>\(319-x=48+x-23=25+x\)

=>\(x+25=319-x\)

=>\(x+x=319-25\)

=>\(2x=294\)

=>\(x=\dfrac{294}{2}=147\)

c: \(-\left(-x-6+85\right)=\left(x+51\right)-54\)

=>\(-\left(-x+79\right)=x+51-54\)

=>x-79=x-3

=>-79=-3(vô lý)

=>\(x\in\varnothing\)

d: \(-\left(35-x\right)-\left(37-x\right)=33-x\)

=>\(-35+x-37+x=33-x\)

=>2x-72=-x+33

=>\(2x+x=33+72\)

=>3x=105

=>\(x=\dfrac{105}{3}=35\)

a)
305 - x + 14 = 48 + (x - 23)
<=>319-x =48+x-23
<=>319-x=25+x
Chuyển vế đổi dấu, Ta có:
-2x=-294
<=>x=147
Vậy giá trị của x là 147

Còn câu b) thì mình chịu SORRY bạn nhé ! Chúc bạn học tốt .

\(a,305-x+14=48+\left(x-23\right)\)

\(\Leftrightarrow-x-x=48-23-14-305\)

\(\Leftrightarrow-2x=-294\)

\(\Leftrightarrow x=147\)

\(b,-\left(35-x\right)-\left(37-x\right)=33-x\)

\(\Leftrightarrow-35+x-37+x=33-x\)

\(\Leftrightarrow2x+x=33+35+37\)

\(\Leftrightarrow3x=105\)

\(\Leftrightarrow x=35\)

Tìm x, biết:

a, 305 - x + 14 = 48 + ( x - 23 )

<=>319-x=25+x

<=>x=-147

b, - ( 35 - x ) - ( 37 - x ) = 33 - x

<=>-72+2x=33-x

<=>2x+x=33+72

<=>3x=105

<=>x=35

1,x-43=(35-x)-48

=>x-43=35-x-48

=>x+x=35-48+43

=>2x=30

=>x=15

Vậy x=15

2,305-x+14=48+(x-23)

=>305-x+14=48+x-23

=>305+14+23-48=x+x

=>294=2x

=>x=294:2

=>x=147

3,-(x-6+85)=(x+51)-54

=>-x+6-85=x+51-54

=>6-85-51+54=x+x

=>-76=2x

=>x=(-76):2

=>x=-38

4,-(35-x)-(37-x)=33-x

=>-35+x-37+x=33-x

=>-35+(-37)+(-33)=-x-x-x

=>-105=-3x

=>x=(-105):(-3)

=>x=35

5,13-\(|x|=|-4|\)

=>13-\(|x|\)=4

=>13-4=\(|x|\)

=>9=\(|x|\)

=>x=9 hoặc x=-9

5) 13 - |x| = |-4|

=> 13 - |x| = 4

|x| = 13-4 = 9

Vậy x=9 hoặc x=-9

4) - (35-x) - (37-x) = 33-x

<=>-35 + x - 37 + x = 33-x

<=> -35 - 37 + x + x = 33-x

-72 + 2x = 33 - x

Theo quy tắc chuyển vế, ta có

-72 - 33 = - 2x + x

-105 = - (2x+x)

-105 = -3x

=> x = (-105) : (-3) = 35

Vậy x=35

Mk chỉ làm đc hai câu thôi. Mk có việc nên ko thể làm tiếp đc cho bạn nữa nha...

a, x - 43 = ( 35 - x ) - 48

\(x-43=35-x-48\)

\(x+x=35-48+43\)

\(2x=30\)

\(x=15\)

b, 305 - x + 14 = 48 + ( x - 23 )

\(305-x+14=48+x-23\)

\(-x-x=48-23-14-305\)

\(-2x=-294\)

\(x=147\)

c, ( x - 6 + 85 ) = ( x + 51 ) - 54

\(x-6+85=x+51-54\)

\(x-x=51-54-85+6\)

\(0=-82\)

\(x\in\varnothing\)

d, -( 35 - x ) - ( 37 - x ) = 33 - x

\(-35+x-37+x=33-x\)

\(x+x+x=33+37+35\)

\(3x=105\)

\(x=35\)

e, - 12. ( x - 5 ) + 7 . ( 3 - x ) = 5

\(-12x+60+21-7x=5\)

\(-12x-7x=5-21-60\)

\(-19x=-76\)

\(x=4\)

f, 30. ( x+ 2 ) - 6 . ( x - 5 ) - 24 = 100

\(30x+60-6x+30-24=100\)

\(30x-6x=100+24-30-60\)

\(24x=34\)

\(x=\frac{17}{12}\)

chúc bạn học tốt

1, ( - 12 ) - ( 13 - x ) = - 15 - ( - 17 )

=> - 12  - 13 + x = - 15 + 17

=> - 25 + x = 2

=> x = 2 + 25 

=> x = 27 

2, 305 - x + 14 = 48 + ( x - 23 )

=> 305 - x + 14 = 48 + x - 23

=> x + x = 305 + 14 - 48 + 23

=> 2x = 294

=> x = 147

3, - ( x - 6 + 85 ) = ( x + 51 ) - 54

=> - x + 6 - 85 = x + 51 - 54

=> x + x = 6 - 85 - 51 + 54

=> 2x = - 76

=> x = - 38

4, - ( 35 - x ) - ( 37 - x ) = 33 - x

=> - 35 + x - 37 + x = 33 - x

=> x + x + x = 33 + 35 + 37

=> 3x = 105

=> x = 35

1.    x=-27

2.   x=147

3.   x=41

4    x=35 

Câu 1

(-12)-(3-x)=-15-(-17)

-12-3+x=-15+17

-15+x=2

x=17

Câu 2

305-x+14=48+(x-23)

319-x=25+x

2x=294

x=147

các câu còn lại giông nên mk ch đáp án

3,-38

4,35

a) Ta có: x-43=(35-x)-48

⇔x-43=35-x-48

⇔x-43=-x-13

⇔x-43+x+13=0

⇔2x-30=0

⇔2(x-15)=0

mà 2≠0

nên x-15=0

hay x=15

b) Ta có: 305-x+14=48+(x-23)

⇔319-x=48+x-23

⇔319-x=x+25

⇔319-x-x-25=0

⇔-2x+294=0

⇔-2x=-294

hay x=147

Vậy: x=147

c) Ta có: -(x-6+85)=(x+51)-54

⇔-x+6-85=x+51-54

⇔-x-79=x-3

⇔-x-79-x+3=0

⇔-2x-76=0

⇔-2x=76

hay x=-38

Vậy: x=-38

d) Ta có: -(35-x)-(37-x)=33-x

⇔-35+x-37+x-33+x=0

⇔3x-105=0

⇔3(x-35)=0

mà 3≠0

nên x-35=0

hay x=35

Vậy: x=35

e) Ta có: 13-|x|=|-4|

⇔13-|x|=4

⇔|x|=9

⇔x∈{9;-9}

Vậy: x∈{9;-9}

f) Ta có: |x|-3+6=16

⇔|x|+3=16

⇔|x|=13

hay x∈{-13;13}

Vậy: x∈{-13;13}

g) Ta có: 35-|2x-1|=14

⇔|2x-1|=21

⇔\(\left[{}\begin{matrix}2x-1=21\\2x-1=-21\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=22\\2x=-20\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=11\\x=-10\end{matrix}\right.\)

Vậy: x∈{11;-10}

h) Ta có: |3x-2|+5=9-x

⇔|3x-2|+5-9+x=0

⇔|3x-2|-4+x=0

⇔|3x-2|=0-(-4+x)

⇔|3x-2|=4-x

⇔\(\left[{}\begin{matrix}3x-2=4-x\\3x-2=x-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}3x-2-4+x=0\\3x-2-x+4=0\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}4x-6=0\\2x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}4x=6\\2x=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{3}{2}\left(ktm\right)\\x=-1\left(tm\right)\end{matrix}\right.\)

Vậy: x=-1

\(x\) + (-31) - (42) = -45

\(x\) - (31 + 42) = -45

\(x\) - 73 = -45

\(x\)       = -45 + 73

\(x\)      = 28

305 - \(x\) + 14  = 48 + (\(x\) - 23)

(305  + 14) - \(x\) = (48 - 23) + \(x\)

319 - \(x\)           = 25 + \(x\) 

\(x\) + \(x\)              = 319 - 25

2\(x\)                  = 294

   \(x\)                 = 294 : 2

   \(x\)                 = 147

\(x-43=\left(35-x\right)\) - 48

\(x\) - 43 = 35 - \(x\) - 48

\(x\) - 43 = - (48 - 35) - \(x\)

\(x\) - 43  = - 13 - \(x\)

\(x\) + \(x\)    = -13 + 43

2\(x\)         = 30

  \(x\)         = 30 : 2

  \(x\)         = 15

x + (-31) - 42 = -45

x - 73 = -45

x = -45 + 73

x = 28

-------

305 - x + 14 = 48 + (x - 23)

319 - x = 48 + x - 23

-x - x = 25 - 319

-2x = -294

x = -294 : (-2)

x = 147

--------

x - 43 = (35 - x) - 48

x = 35 - x - 48 + 43

x + x = 30

2x = 30

x = 30 : 2

x = 15

$x$ + (-31) - (42) = -45

$x$ - (31 + 42) = -45

$x$ - 73 = -45

$x$       = -45 + 73

$x$      = 28

305 - $x$ + 14  = 48 + ($x$ - 23)

(305  + 14) - $x$ = (48 - 23) + $x$

319 - $x$           = 25 + $x$ 

$x$ + $x$              = 319 - 25

2$x$                  = 294

   $x$                 = 294 : 2

   $x$                 = 147

$x-43=\left(35-x\right)$ - 48

$x$ - 43 = 35 - $x$ - 48

$x$ - 43 = - (48 - 35) - $x$

$x$ - 43  = - 13 - $x$

$x$ + $x$    = -13 + 43

2$x$         = 30

  $x$         = 30 : 2

  $x$         = 15