Question

Tìm tổng các số nguyên x biết :

a, -5 ≤ x + 8 ≤ 5

b, 2004 ≤ | 2x | ≤ 2010

Answer 1

\(a) \) \(-5\le x+8\le5\)

\(\Leftrightarrow\)\(x+8\in\left\{\pm5;\pm4;\pm3;\pm2;\pm1;0\right\}\)

\(x\in\left\{-3;-13;-4;-12;-5;-11;-6;-10;-7;-9;-8\right\}\)

\(b) \)

\(2004\le\left|2x\right|\le2010\)

\(\Leftrightarrow\left|2x\right|\in\left\{2004;2006;2008;2010\right\}\)

\(\Leftrightarrow2x\in\left\{\pm2004;\pm2006;\pm2008;\pm2010\right\}\)

\(\Leftrightarrow x\in\left\{\pm1002;\pm1003;\pm1004;\pm1005\right\}\)