Hàm số \(y = x + \left| x \right|\) được viết lại:

A. \(y = \left\{ \begin{array}{l}
2x\,\,\,\,\,\,{\rm{khi}}\,\,x \le 0\\
0\,\,\,\,\,\,\,\,\,\,{\rm{khi }}x > 0
\end{array} \right.\)

B. \(y = \left\{ \begin{array}{l}
0\,\,\,\,\,\,\,{\rm{khi}}\,\,x \le 0\\
2x\,\,\,\,{\rm{khi }}x > 0
\end{array} \right.\)

C. \(y = \left\{ \begin{array}{l}
 - 2x\,\,\,\,\,\,\,{\rm{khi}}\,\,x \le 0\\
0\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{khi }}x >  - 2
\end{array} \right.\)

D. \(y = \left\{ \begin{array}{l}
x\,\,\,\,\,\,\,{\rm{khi}}\,\,x \le 0\\
2x\,\,\,\,{\rm{khi }}x > 0
\end{array} \right.\)