6x + 4 - l5x l =16
=> \(\left[ \begin{array}{l}6x + 4 - 5x = 16 (khi x>0)\\6x + 4 -(-5x) = 16 (khi x<0)\end{array} \right.\)
=> \(\left[ \begin{array}{l}x = 12(t/m)\\11x = 12\end{array} \right.\)
=> \(\left[ \begin{array}{l}x=12\\x=\frac{12}{11}(loại vì x<0)\end{array} \right.\)
Vậy x = 12