a)x+5=20-5

x+5=15

x=15-5

x=10

b) sai đề

Câu 1:

16 - 18|x| = - 8 - 14|x|

18|x| - 14|x| = 16 + 8

4|x| = 24

|x| = 24 : 4

|x| = 6

x = - 6 hoăc x = 6

Vậy x ∈ {-6; 6}

e) 15-3|4x +2| = 3

3|4x + 2| = 15 - 3

3|4x + 2| = 12

|4x + 2| = 12 : 3

|4x + 2| = 4

4x + 2 = -4 hoặc 4x + 2 = 4

Th1: 4x + 2 = - 4

4x = - 4 - 2

4x = - 6

x = - 6/4

x = - 3/2

Th2: 4x + 2 = 4

4x = 4 - 2

4x = 2

x = 2/4

x = 1/2

Vậy x ∈ {- 3/2; 1/2}

-2.(x-5)-18=20-3.(x+4)

<=> -2x+10-18=20-3x-12

<=>-2x-8=8-3x

<=>-2x+3x=8+8

<=>x=16

Vậy x=16

Học tốt!!!

#Bo_lienminhmeovatrau

tìm x biết

-2.(x-5)-18=20-3.(x+4)

-2x+10-18=20-3x-12

-2x+3x=20-12-10+18

        x=16

Vậy x=16

-2(-x - 5) + 18 = 20 - 3(x + 4)

<=> 2x + 10 + 18 = 20 - 3x - 12

<=> 2x + 3x = 20 - 12 - 10 - 18

<=> 5x = -20

<=> x = -4 (TM)

-2(-x - 5) + 18 = 20 - 3(x + 4)

=> 2x + 10 + 18 = 20 - 3x - 12

=> 2x + 28 = -3x +  8

=> 2x + 3x = 8 - 28

=> 5x = -20

=> x = -20 : 5 = -4

<=> 2x + 10 + 18 = 20 - 3x - 12

<=> 2x + 3x          = 20 - 12 - 10 - 18

<=> 5x                  = -20

<=>  x                   = -20 : 5

<=>  x                   = -4

-2(-x - 5) + 18 = 20 - 3(x + 4)

2x + 10 + 18 = 20 - 3x - 12

2x + 3x = 20 - 12 - 10 - 18

5x = -20

x = -20 : 5

x = -4

uk

Câu 1:

16 - 18|x| = - 8 - 14|x|

18|x| - 14|x| = 16 + 8

4|x| = 24

|x| = 24 : 4

|x| = 6

x = - 6 hoăc x = 6

Vậy x ∈ {-6; 6}

10 - 2(4-3x) = - 4

     -2(4-3x ) = -4 - 10

     -2(4-3x)= - 14

      2(4-3x) = 14

         4-3x = 14  :2

        4-3x = 7

          -3x = 7- 4