`a) 5 - | x - 1/2 | = 0`
`| x - 1/2 | = 5`
\(\left[ \begin{array}{l}x-\dfrac{1}{2}=5\\x-\dfrac{1}{2}=-5\end{array} \right.\)
\(\left[ \begin{array}{l}x=5+\dfrac{1}{2}\\x=-5+\dfrac{1}{2}\end{array} \right.\)
\(\left[ \begin{array}{l}x=5+\dfrac{1}{2}\\x=-5+\dfrac{1}{2}\end{array} \right.\)
\(\left[ \begin{array}{l}x=\dfrac{11}{2}\\x=\dfrac{-9}{2}\end{array} \right.\)
`b) | x - 2 | - | x + 2 | = 0`
`| x - 2 | = | x + 2 |`
\(\left[ \begin{array}{l}x-2=x+2\\x-2=-x-2\end{array} \right.\)
\(\left[ \begin{array}{l}-2=2 (\text{vô lí})\\2x=0\end{array} \right.\)
`=> x = 0`
`c) | 3x + 1 | = 0`
`3x + 1 = 0`
`3x = -1`
`x = -1/3`
