Question

|2x|=x+3 vậy x bằng bao nhiêu ạ???

Answer 1

Ta có: \(\left|2x\right|=x+3\)

\(\Leftrightarrow\left[{}\begin{matrix}2x=x+3\left(x\ge0\right)\\-2x=x+3\left(x< 0\right)\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-x=3\\-2x-x=3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\left(nhận\right)\\x=-1\left(nhận\right)\end{matrix}\right.\)

Vậy: S={3;-1}