Đáp án:
a, `|2x-5|=4`
⇔\(\left[ \begin{array}{l}2x-5=4\\2x-5=-4\end{array} \right.\)
⇔\(\left[ \begin{array}{l}2x=9\\2x=1\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=9/2\\x=1/2\end{array} \right.\)
b, `1/3-|5/4-2x|=1/4`
`⇔|5/4-2x|=1/12`
⇔\(\left[ \begin{array}{l}5/4-2x=1/12\\5/4-2x=-1/12\end{array} \right.\)
⇔\(\left[ \begin{array}{l}2x=7/6\\2x=4/3\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=7/12\\x=2/3\end{array} \right.\)
