Question

\(|-2,5x|=x-12\)

Answer 1

`|-2,5x|=x-12(x>=12)`

`+)-2,5x=x-12`

`<=>3,5x=12`

`<=>x=24/7(l)`

`+)2,5x=x-12`

`<=>1,5x=-12`

`<=>x=-8`

Vậy pt vô nghiệm

Answer 2

I-2,5xI = x -12

TH1 : -2,5x =x -12 (x <0)

<=> -3,5x =-12 => x=\(\dfrac{24}{7}\) ktm 

TH2 : 2,5x = x -12 (x>0) 

1,5x=-12 => x=\(\dfrac{-24}{5}\) ktm

vậy x ∈∅