1) \(\left(3x-1\right)^3=125\)

=>\(\left(3x-1\right)^3=5^3\)

=>\(3x-1=5\)

         \(3x=6\)

           \(x=2\)

2) 231 - ( x - 8 ) = 1339 : 13

  231 - (  x - 8 ) = 103

231 - 103 = x - 8

      128  = x - 8 

       x    = 128 + 8

        x   = 136

a. \(2x-138=2^3.3^2\\ \Leftrightarrow2x-138=72\\ \Leftrightarrow2x=210\\ \Leftrightarrow x=105\)

b. \(231-\left(x-6\right)=1339:13\\ \Leftrightarrow231-\left(x-6\right)=103\\ \Leftrightarrow x-6=128\\ \Leftrightarrow x=134\)

a) 2 * x - 138 = 8 * 9

2 * x - 138 = 72

2 * x = 210

x = 105

b) 231 - ( x - 6 ) = 1339 : 13

231 - x + 6 = 103

237 - x = 103

x = 134

c) 70 - 5 * ( x-3) = 45

5 * (x-3) = 25

x - 3 = 5

x = 8

cac phan con lai bn lm tuong tu nha

* 2*X-138=8*9

   <=> 2*X-138=72

   <=> 2*X=72+138

   <=> 2*X=210

   <=> X=210/2=105

*231-(X-6)=1339:13

 <=> 231-(X-6)=103

<=> X-6=231-103

<=>X-6=128

<=>X=128+6=134

*70-5*(X-3)=45

<=>5*(X-3)=70-45

<=>5*(X-3)=25  

<=>X-3=25/5

<=>X-3=5

<=>X=8

*10+2*X=16

<=>2*X=16-10

<=>2*X=6

<=>X=6/2=3

\(2x-138=72\)

\(2x=72+138\)

\(2x=210\)

\(x=105\)

\(231-\left(x-6\right)=103\)

\(x-6=231-103\)

\(x-6=128\)

\(x=134\)

\(5\left(x-3\right)=70-45\)

\(5\left(x-3\right)=25\)

\(x-3=5\)

\(x=5+3\)

\(x=8\)

\(2x=16-10\)

\(2x=6\)

\(x=3\)

a) 124 + (118 - x) = 217

118 - x = 217 - 124

118 - x = 93

x = 118 - 93

x = 25

b) 156 - (x + 61) = 82

x + 61 = 156 - 82

x + 61 = 74

x = 74 - 61

x = 13

c) 219 - 7(x + 1) = 100

7(x + 1) = 219 - 100

7(x + 1) = 119

x + 1 = 119 : 7

x + 1 = 17

x = 17 - 1

x = 16

d) (3x - 6).3 = 3⁴

3x - 6 = 3⁴ : 3

3x - 6 = 3³

3x - 6 = 27

3x = 27 + 6

3x = 33

x = 33 : 3

x = 11

e) 231 - (x - 6) = 1339 : 13

231 - (x - 6) = 103

x - 6 = 231 - 103

x - 6 = 128

x = 128 + 6

x = 134

a) 124 + (118 - x) = 217

118 - x = 217 - 124

118 - x = 93

x = 118 - 93

x = 25

b) 156 - (x + 61) = 82

x + 61 = 156 - 82

x + 61 = 74

x = 74 - 61

x = 13

c) 219 - 7(x + 1) = 100

7(x + 1) = 219 - 100

7(x + 1) = 119

x + 1 = 119 : 7

x + 1 = 17

x = 17 - 1

x = 16

d) (3x - 6) . 3 = 3⁴

(3x - 6) . 3 = 81

(3x - 6) = 81 : 3

(3x - 6) = 27

3x = 27 + 6

3x = 33

x = 33 : 3 

x = 11

e) 231 - (x - 6) = 1339 : 13

231 - (x - 6) = 103

(x - 6) = 231 - 103

x - 6 = 128

x = 128 + 6

x = 134

cô cấm dùng máy tính -) 

lớp 9 ms đc dùng:_)

231 - ( x - 6 ) = 1339 : 13

231 - ( x - 6 ) = 103

x - 6 = 231 - 103

x - 6 = 128

x = 128 + 6

x = 134

2 . x - 138 = 2³ . 3²

2 . x - 138 = 8 . 9

2 . x - 138 = 72

2 . x = 72 + 138

2 . x = 210

x = 210 : 2

x = 105

231 - ( x - 6 ) = 1339 : 13

231 - (x - 6) = 1339/13

x - 6 = 231 - 1339/13

x - 6 = 128

x = 128 + 6

x = 134

2x-138=2³.3²

2x-138=72

2x=72+138

2x=210

x=210:2

x=105

231-(x-6)=1339:13

231-(x-6)=103

x-6=231-103

x-6=128

x=128+6

x=134

A) 2.x-138=2³.3²

    2.x-138=8.9

    2.x-138=81

    2.x      =81+138

    2.x      =219

             x=219:2

             x=109,5

B) 231-(x-6)=1339:13

    231-(x-6)=103

           x-6 =231-103

           x-6 =128

              x =128+6

              x=134

a. 2.x-138=2³.3²

2.x-138=8.9

2.x-138=72

2.x=72+138

2.x=210

x=210:2

x=105.

b. 231-(x-6)=1339:13

231-(x-6)=103

x-6=231-103

x-6=128

x=128+6

x=134

bn nhớ cho mk nha!

a)\(2x-138=72\)

\(=>2x=210\)

\(=>x=210:2=105\)

b)\(231-\left(x-6\right)=103\)

\(=>\left(x-6\right)=231-103\)

\(=>\left(x-6\right)=128\)

\(=>x=128+6=134\)

a) 2x-138=2³.3²

2x-138=72

2x=72+138

2x=210

x=210/2

x=105

b)231-(x-6)=1339:13

231-(x-6)=103

(x-6)=231-103

x-6=128

x=128+6

x=134