Đáp án:
`2 | 2x - 3| = \frac{1}{2}`
` | 2x - 3| = \frac{1}{2}:2`
` | 2x - 3| = \frac{1}{4}`
`⇒`\(\left[ \begin{array}{l} 2x - 3 = \frac{1}{4} \\ 2x - 3 = -\frac{1}{4}\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l} 2x = \frac{1}{4}+ 3 \\ 2x = -\frac{1}{4}+3\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l} 2x = \frac{13}{4} \\ 2x = \frac{11}{4}\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l} x = \frac{13}{4} : 2\\ x = \frac{11}{4} :2\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l} x = \frac{13}{8} \\ x = \frac{11}{8}\end{array} \right.\)
Vậy `x ∈ {\frac{13}{8} ; \frac{1}{8}}`
`7,5 - 3|5 - 2x| = -4,5`
`3|5 - 2x| = 7,5 + 4,5`
` 3|5 - 2x| = 12`
`|5 - 2x| = 12 : 3`
`|5 - 2x| = 4`
`⇒`\(\left[ \begin{array}{l} 5 - 2x = 4 \\ 5 - 2x = -4\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l} 2x = 5 -4 \\ 2x = 5 + 4\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l} 2x = 1\\ 2x = 9\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l} x = 1 : 2\\ x = 9 : 2\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l} x = 0,5 \\ x = 4,5\end{array} \right.\)
Vậy `x ∈ {0,5 ; 4,5}`
