| 2x + 1 | - 19 = -7
⇔ | 2x + 1 | = -7 + 19
⇔ | 2x + 1 | = 12
⇔ \(\left[ \begin{array}{l}2x+1=12\\2x+1=-12\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}2x=11\\2x=-13\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=5,5\\x=-6,5\end{array} \right.\)
Vậy...
