\( 6x + 4 - \left| {5x} \right| = 16\\ \Leftrightarrow 6x - 5\left| x \right| = 12\\ \Leftrightarrow \left[ \begin{array}{l} \left\{ \begin{array}{l} x \ge 0\\ 6x - 5x = 12 \end{array} \right.\\ \left\{ \begin{array}{l} x < 0\\ 6x - 5\left( { - x} \right) = 12 \end{array} \right. \end{array} \right. \Leftrightarrow \left[ \begin{array}{l} \left\{ \begin{array}{l} x \ge 0\\ x = 12 \text{(nhận)} \end{array} \right.\\ \left\{ \begin{array}{l} x < 0\\ x = \dfrac{{12}}{{11}} \text{(loại)} \end{array} \right. \end{array} \right. \)
