Question

tìm x biết:

\(3\left|x\right|-x=12\)

Answer 1

\(3\left|x\right|-x=12\)

\(\Rightarrow3x-x=12\)

\(\Rightarrow x\left(3-1\right)=12\)

\(\Rightarrow2x=12\)

\(\Rightarrow x=6\)

Vậy......

Answer 2

ta có 3.|x| - x = 12

⇒ \(\left[{}\begin{matrix}-3x-x=12\\3x-x=12\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}-4x=12\\2x=12\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-3\\x=6\end{matrix}\right.\)

vậy x ∈ {-3;6}