Đáp án : $a$) $S$ $=$ `{6;-1}`
$b$) `S={-1/2}`
Giải thích:
$a$) `|2x-5| - 7 =0 `
`⇔ |2x-5| = 7`
`⇔ 2x-5 = ± 7`
`⇒` \(\left[ \begin{array}{l}2x=12\\2x=-2\end{array} \right.\)
$⇒$ \(\left[ \begin{array}{l}x=6\\x = -1\end{array} \right.\)
Vậy $S$ $=$ `{6;-1}`
$b$) `7 - |8 - 3| = 2x+3`
`⇔ 7 - 5 = 2x+3`
`⇔ 2x+3 = 2`
`⇔ 2x = -1`
`⇔ x = -1/2`
Vậy `S={-1/2}`