<=>3.|5-x|=12
<=> |5-x|=4
<=> 5-x = 4 hoặc x-5 = 4
<=> x=1 hoặc x=9
Ta có :\(3.\left|5-x\right|=\left|-12\right|\)
\(\Leftrightarrow3.\left|5-x\right|=12\)
\(\Leftrightarrow\left|5-x\right|=\dfrac{12}{3}=4\)
\(\Rightarrow\left[{}\begin{matrix}5-x=4\\5-x=-4\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=1\\x=9\end{matrix}\right.\)
Vậy x=1 hoặc x=9
3.| 5-x | = |-12|
=> 3.| 5-x | = 12
=> |5-x | = 4
TH1: 5-x = 4 TH2: 5-x = -4
x= 5 - 4 x= 5-( -4 )
x= 1 x= 9
Vậy x=1 hoặc x=9