a/ \(3x+\left|4x+3\right|=5\)
\(\Leftrightarrow4x+3=5-3x\)
\(\Leftrightarrow\left[{}\begin{matrix}4x+3=5-3x\\4x+3=-5+3x\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}4x+3x=5-3\\4x-3x=-5-3\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}7x=2\\x=-8\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{7}\\x=-8\end{matrix}\right.\)
Vậy ..........
b/ \(x-\left|x+1\right|=4\)
\(\Leftrightarrow\left|x+1\right|=x-4\)
\(\Leftrightarrow\left[{}\begin{matrix}x+1=x-4\\x+1=-x+4\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x-x=-4-1\\x+x=4-1\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}0x=-5\left(loại\right)\\2x=3\end{matrix}\right.\)
\(\Leftrightarrow x=\dfrac{3}{2}\)
Vậy ..
3x+\(\left|4x+3\right|\)=5
TH1:\(\)4x+3=5-3x
\(\Rightarrow\)4x+3x=5-3
\(\Rightarrow\)7x=2\(\Rightarrow\)\(\dfrac{2}{7}\)
TH2:4x+3=-5+3x
\(\Rightarrow\)4x-3x=-5-3
\(\Rightarrow\)x=-8
