Question

a) I x-5 I = 2,9

b) I 7+5x I + 2 = 2x - 1

c) I 1/3.x I . I -2,7 I = I -9 I

d) I x+ 2/3 I + I y-1/2 I = 0

 

 

 

Answer 1

a) I x - 5 I = 2.9 

1) x- 5 = 2.9 => x= 2.9 + 5 => x = 7.9

2) x - 5 = -2.9 => x = -2.9 + 5 => x = 2.1

Vậy x= 7.9 hoặc x= 2.1

b)  I 7+5x I + 2 = 2x - 1

 I 7+5x I  =  2x - 1 - 2

 I 7+5x I  =  2x - 3

1) 5x + 7 = 2x- 3  => 5x - 2x = -3-7 => 3x = -10  => x= -10/3 

2) 5x + 7 = -2x  + 3 => 5x + 2x = 3-7 => 7x = -5 => x= -5/7

c) I 1/3.x I . I -2,7 I = I -9 I

I 1/3x I . 2.7 = 9

I 1/3x I = 9 : 2.7

 I 1/3 x I = 10/3

1) 1/3x = 10/3

x = 10/3 . 3

x= 10

1/3x = -10/3 

x= -10/3 . 3

x= -10

Vậy ......