`1)`
`|x + 1/5| - 4 = -2`
`⇔ |x + 1/5| = 2`
⇒ \(\left[ \begin{array}{l}x + 1/5 = 2\\x + 1/5 = -2\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}x = 9/5\\x = -11/5\end{array} \right.\)
`Vậy S = {9/5 ; -11/5}`
`2)`
`-3/4 - |4/5 - x| = -1`
`⇔ |4/5 - x| = 1 - 3/4 = 1/4`
⇒ \(\left[ \begin{array}{l}4/5 - x = 1/4\\4/5 - x = -1/4\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}x = 11/20\\x = 21/20\end{array} \right.\)
`Vậy S = {11/20 ; 21/20}`
`3)`
`|-1/2 - x| = 1/3`
⇒ \(\left[ \begin{array}{l}-1/2 - x = 1/3\\-1/2 - x = -1/3\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}x = -5/6\\x = -1/6\end{array} \right.\)
`Vậy S = {-5/6 ; -1/6}`
