\(1.311-x+82=46+\left(x-21\right)\\ 311+82-x=46-21+x\\ 393-x=25+x\\ 393-x-25-x=0\\ 393-25-x-x=0\\ 368-2x=0\\ \Rightarrow-2x=368\\ x=368:\left(-2\right)\\ x=-184\)

\(2.-\left(x-3+85\right)=\left(x+70-71\right)-5\\ -x+3-85=x+70-71-5\\ -x-82=x-6\\ -x-82-x+6=0\\ -2x-76=0\\ -2x=76\\ x=76:\left(-2\right)\\ x=-38\)

\(3.\left(-x+821+534\right)=499+\left(x-84\right)\\ -x+821+534=499+x-84\\ -x+1355=x+415\\ -x+1355-x-415=0\\ -2x+940=0\\ -2x=-940\\ x=-940:\left(-2\right)\\ x=470\)

\(4.x+96=\left(443-x\right)-447\\x+96=443-x-447\\ x+96=-x-4\\ x+96+x+4=0\\ 2x+100=0\\ 2x=-100\\ x=-100:2\\ x=-50 \)

a) x - 96 = (443 - x) - 15

x - 96 = 443 - x - 15

x + x = 443 -15 + 96

2x = 524

x = 524 : 2

x = 262

b) (x  -12) - 15 = (20 - 7) - (18 + x)

x - 12 - 15 = 20 - 7 - 18 - x

x + x = 20 - 7 - 18 + 12 + 15

2x = 22

x = 22 : 2

x = 11

c) 311 - x + 82 = 46 + (x - 21)

311 - x + 82 = 46 + x - 21

-x - x = 46 - 21 - 311 - 81

-2x = -367

x = -367 : (-2)

x = 183,5

d) -(x - 3 + 85) = (x + 70 - 71) - 5

-x + 3 - 85 = x + 70 - 71 - 5

-x - x = 70 - 71 - 5 - 3 + 85

-2x = 76

x = 76 : (-2)

x = -38

e,f làm tương tự

a) x - 96 = (443 - x) - 15

x - 96 = 443 - x - 15

x + x = 443 -15 + 96

2x = 524

x = 524 : 2

x = 262

b) (x  -12) - 15 = (20 - 7) - (18 + x)

x - 12 - 15 = 20 - 7 - 18 - x

x + x = 20 - 7 - 18 + 12 + 15

2x = 22

x = 22 : 2

x = 11

c) 311 - x + 82 = 46 + (x - 21)

311 - x + 82 = 46 + x - 21

-x - x = 46 - 21 - 311 - 81

-2x = -367

x = -367 : (-2)

x = 183,5

d) -(x - 3 + 85) = (x + 70 - 71) - 5

-x + 3 - 85 = x + 70 - 71 - 5

-x - x = 70 - 71 - 5 - 3 + 85

-2x = 76

x = 76 : (-2)

x = -38

e,f làm tương tự

a) x - 96 = (443 - x) - 15

x - 96 = 443 - x - 15

x + x = 443 -15 + 96

2x = 524

x = 524 : 2

x = 262

b) (x  -12) - 15 = (20 - 7) - (18 + x)

x - 12 - 15 = 20 - 7 - 18 - x

x + x = 20 - 7 - 18 + 12 + 15

2x = 22

x = 22 : 2

x = 11

c) 311 - x + 82 = 46 + (x - 21)

311 - x + 82 = 46 + x - 21

-x - x = 46 - 21 - 311 - 81

-2x = -367

x = -367 : (-2)

x = 183,5

d) -(x - 3 + 85) = (x + 70 - 71) - 5

-x + 3 - 85 = x + 70 - 71 - 5

-x - x = 70 - 71 - 5 - 3 + 85

-2x = 76

x = 76 : (-2)

x = -38

e,f làm tương tự

a) 311 - x + 82 = 46 + (x - 21)

311 - x + 82 = 46 + x - 21

-x - x = 46 - 21 - 311 - 82

-2x = -368

x = -368 : (-2)

x = 184

b) -(x - 3 + 85) = (x + 70 - 71) - 5

-x + 3 - 85 = x + 70 - 71 - 5

-x - x = 70 - 71 - 5 - 2 + 85

-2x = 77

a,    (x-12) -15 = (20-7) - (18+x)

<=> x - 12 - 15 = 13 - 18 - x 

<=> 2x = 22

<=> x = 11

b,     x- 96  = ( 443 - x) - 15

<=> x - 96 = 443 - x - 15

<=> 2x = 524

<=> x = 262

c,     311 - x + 82 = 46 + ( x- 21)

<=> 311 - x + 82 = 46 + x - 21

<=> 2x = 368

<=> x = 184

e,     ( - x + 821 + 534 ) = 499 + ( x-84)

<=> - x + 821 + 534 = 499 + x - 84

<=> 2x = 940

<=> x = 470

f,      x + 96 = ( 443 - x) - 447 

<=> x + 96 = 443 - x - 447

<=> 2x = - 100

<=> x = - 50

d,     - ( x - 3 + 85) = ( x + 70 - 71) -5

<=> - x + 3 - 85 = x + 70 - 71 - 5

<=> 2x = - 76

<=> x = - 38

a) 311 - x + 82 = 46 + (x - 21)

=> 393 - x = 25  + x

=> 393 - 25 = x + x

=> 368 = 2x

=>x = 368 : 2

=> x = 184

b) -(x - 3 + 85) = (x + 70 - 71) - 5

=> -x + 3 - 85 = x + 70 - 71 - 5

=> -x - 82 = x - 6

=> -x -x = 6 + 82

=> -2x = 88

=> x = 88 : (-2)

=> x = -44

\(311-x+82=46+\left(x-21\right)\)

\(393-x=36+x-21\)

\(393-36+21=2x\)

\(x=139\)

a)311-x+82=46+(x-21)      

  311 - x + 82 = 46 + x - 21 

  -x - x = 46 - 21 - 311 - 82 

  -2x    = -368

     x    = 184

 b) -(x-3+85)=(x+70-71)-5

     - x + 3 - 85 = x + 70 - 71 - 5 

     - x - x = 70 - 71 - 5 + 85 - 3 

     -2x    = 76

      x      = -38

c)(-x+821+534)=499+(x-84)        

   - x + 821 + 534 = 499 + x - 84 

    - x - x = 499 - 84 - 534 - 821 

     -2x    =   -940

     x       = 470

c)x+96=(443-x)-447

 x + 96 = 443 - x - 447 

 x + x    = 443 - 447 - 96 

  2x      = -100

    x      = -50

\(\dfrac{177}{x}-\dfrac{96}{x}+\dfrac{21}{x}=6\left(x\ne0\right)\\ \dfrac{177-96+21}{x}=6\\ \dfrac{102}{x}=6\\ 6\times x=102\\ x=102:6=17\)

\(\dfrac{177}{x}-\dfrac{96}{x}+\dfrac{21}{x}=6\)

\(\dfrac{1}{x}\left(177-96+21\right)=6\)

\(102:x=6\)

\(x=102:6\)

\(x=17\)

\(\dfrac{177}{x}\) - \(\dfrac{96}{x}\) + \(\dfrac{21}{x}\) = 6

\(\dfrac{1}{x}\) \(\times\)( 177 - 96 + 21) = 6

\(\dfrac{1}{x}\) \(\times\) (81 + 21) = 6

\(\dfrac{1}{x}\) \(\times\) 102 = 6

\(\dfrac{102}{x}\)         = 6

\(x\)              = 102 : 6

\(x\)              = 17

phá ngoặc. chuyển vế đổi dấu là đc

134;135;136 SBT 6 DAY

:-) 

me too

\(311-x+82=46+x-21\)

           \(393-x=x+25\)

                 \(x+x=393-25\)

                       \(2x=368\)

                         \(x=184\)