`|4x+3| - x = 15`
`=> |4x+3| = 15 + x`
`=>` \(\left[ \begin{array}{l}4x+3 = 15 + x\\4x+3 = -15 -x\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}4x -x = 15 -3\\4x+x = -15-3 \end{array} \right.\)
`=>` \(\left[ \begin{array}{l}3x = 12\\5x= -18 \end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=4\\x= \frac{-18}{5} \end{array} \right.\) (T/m)
Vậy `x = 4` hoặc `x = -18/5`
(Chúc bạn học tốt)