Đáp án + Giải thích các bước giải:
a)
`|x-7/2|-1/4=5/4`
`=>|x-7/2|=5/4+1/4`
`=>|x-7/2|=3/2`
`=>` \(\left[ \begin{array}{l}x-\frac{7}{2}=\frac{3}{2}\\x-\frac{7}{2}=\frac{-3}{2}\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=\frac{3}{2}+\frac{7}{2}\\x=\frac{-3}{2}+\frac{7}{2}\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=5\\x=2\end{array} \right.\)
Vậy `x∈{5;2}`
b)
`(-2)/5<x/5<4/10`
`=>(-4)/10<(2x)/10<4/10`
`=>-4<2x<4`
`=>2x∈{-3;-2;-1;0;1;2;3}`
`=>x∈{-2;0;2}`
Vậy `x∈{-2;0;2}`
