Question

Tìm x,biết

|\(\frac{5}{4}\)x - \(\frac{7}{2}\)| - |\(\frac{5}{8}\)x + \(\frac{3}{5}\)| = 0

Answer 1

theo đề:

=> |5/4x-7/2|=|5/8x+3/5|

=> 5/4x-7/2=5/8x+3/5     hoặc 5/4x-7/2=-(5/8x+3/5)

=> 5/4x-5/8x=3/5+7/2      hoặc 5/4x-7/2=-5/8x-3/5

=> (5/4-5/8)x=41/10         hoặc 5/4x+5/8x=-3/5+7/2

=> 5/8x=41/10                 hoặc 15/8x=29/10

=> x=41/10:5/8                 hoặc x=29/10:15/8

=> x=164/25                     hoặc x=116/75

Answer 2

\(\left|\frac{5}{4}x-\frac{7}{2}\right|-\left|\frac{5}{8}x+\frac{3}{5}\right|=0\)

5/4x - 7/2 = 0

=> 5/4x = 7/2 ; x = 14/5

5/8x + 3/5 = 0 

5/8x = -3/5

x = -24/25

Mà -24/25 \(\ne\) 14/5

Nên không có x     

Answer 3

11/4 + 3/2 : |4x - 1/5| = 7/2

3/2 : |4x - 1/5| = 7/2 - 11/4

3/2 : |4x - 1/5| = 3/4

|4x - 1/5| = 3/2 : 3/4

|4x - 1/5| = 2

<=> 4x - 1/5 = 2; -2.

TH1: 4x - 1/5 = 2 => 4x = 2 + 1/5 => 4x = 11/5 => x = 11/20.

TH2: 4x - 1/5 = -2 => 4x = -2 + 1/5 => 4x = -9/5 => x = -9/20.

[Thử lại] Vậy x = 11/20; -9/20.