`-4x-3=|2x+4|(x<=-3/4)`
`<=>` $\left[ \begin{array}{l}2x+4=4x+3\\2x+4=-3-4x\end{array} \right.$
`<=>` $\left[ \begin{array}{l}2x=1\\6x=-7\end{array} \right.$
`<=>` $\left[ \begin{array}{l}x=\dfrac12(l)\\x=-\dfrac76(tm)\end{array} \right.$
Vậy `S={-7/6}`
\(\left|2x+4\right|=2x+4\) khi \(2x+4\ge0\Leftrightarrow x\ge-2\)
Ta được phương trình :
\(-4x-3=2x+4\)
\(\Leftrightarrow-4x-2x=4+3\)
\(\Leftrightarrow-6x=7\Leftrightarrow x=-\dfrac{7}{6}\)(TMĐK)
\(\left|2x+4\right|=-\left(2x+4\right)\) khi \(2x+4< 0\Leftrightarrow x< -2\)
Ta được phương trình :
\(-4x-3=-\left(2x+4\right)\)
\(\Leftrightarrow-4x-3=-2x-4\)
\(\Leftrightarrow-4x+2x=-4+3\)
\(\Leftrightarrow-2x=-1\Leftrightarrow x=\dfrac{1}{2}\)(KTMĐK)
Vậy \(S=\left\{-\dfrac{7}{6}\right\}\)