Question

tìm \(x\in Z\) \(\)sao cho
\(\dfrac{-1}{5}\le\dfrac{x}{40}< \dfrac{-1}{8}\)

Answer 1

⇔−840≤x40≤−540

Mà x

 

Answer 2

\(\dfrac{-1}{5}\le\dfrac{x}{40}\le\dfrac{-1}{8}\)

\(\Leftrightarrow\dfrac{-8}{40}\le\dfrac{x}{40}\le\dfrac{-5}{40}\)

\(\Leftrightarrow-8\le x\le-5\)

Mà x\(\in Z\)

\(\Rightarrow x\in\left\{-8;-7;-6;-5\right\}\)

Vậy ...

Answer 3

\(\dfrac{-1}{5}\le\dfrac{x}{40}< \dfrac{-1}{8}\)

<=>\(\dfrac{-8}{40}\le\dfrac{x}{40}< \dfrac{-5}{40}\)

\(\Leftrightarrow-8\le x< 5\)

Mà \(x\in Z\)

\(\Rightarrow x\in\left\{-8;-7;-6\right\}\)

Vậy