Question

tìm x : 

|-30| - 3.|x|=9

|2.x|+|-18| = 28

Answer 1

|-30| - 3 .|x| = 9

30 - 3 . x = 9

3 . x = 30 - 9

3 . x = 21

     x = 21 : 3

     x = 7

|2.x| +|-18| = 28

2 . x + 18 = 28

2 . x = 28 - 18

2 . x = 10

     x = 10 : 2

     x = 5

Answer 2

|-30| - 3.|x| = 9

30 - 3.x = 9

3.x = 30 - 9

3.x = 21

x = 21 : 3

x = 7

vậy___

Answer 3

|-30| - 3 .|x| = 9

30 - 3 . x = 9

3 . x = 30 - 9

3 . x = 21

     x = 21 : 3

     x = 7

|2.x| +|-18| = 28

2 . x + 18 = 28

2 . x = 28 - 18

2 . x = 10

     x = 10 : 2

     x = 5

hok tốt