1)
\(\left|x\right|=2,3\)
\(\Rightarrow x=\left\{\pm2,3\right\}\)
2) Gọi phân số đó là
\(\dfrac{a}{8}\)
Theo đề bài ta có:
\(\dfrac{-3}{4}< \dfrac{a}{8}< \dfrac{1}{4}\)
\(\dfrac{-6}{8}< \dfrac{a}{8}< \dfrac{2}{8}\)
\(-6< a< 2\)
\(a\in\left\{-5;-4;-3;-2;-1;0;1\right\}\)
\(\dfrac{a}{8}\in\left\{\dfrac{-5}{8};\dfrac{-4}{8};\dfrac{-3}{8};\dfrac{-2}{8}+\dfrac{-1}{8}+\dfrac{0}{8}+\dfrac{1}{8}\right\}\)
Tổng của tất cả các số trên là:
\(\dfrac{-5}{8}+\dfrac{-4}{8}+\dfrac{-3}{8}+\dfrac{-2}{8}+\dfrac{-1}{8}+\dfrac{0}{8}+\dfrac{1}{8}\)
\(=\left(\dfrac{1}{8}+\dfrac{-1}{8}\right)+\left(\dfrac{-5+-4+-3+-2}{8}\right)\)
\(=0+\dfrac{-7}{4}=\dfrac{-7}{4}\)
