Question

[Park Jisa Official]

tìm số tự nhiên x sao cho : 

   4/7 < x/ 10 < x/7

Answer 1

[Thiên]

\(\frac{4}{7}< \frac{x}{10}< \frac{5}{7}\)

\(\Rightarrow\frac{40}{70}< \frac{7x}{70}< \frac{50}{70}\)

\(\Rightarrow40< 7x< 50\)

\(\Rightarrow40:7< x< 50:7\)

\(\Rightarrow5,714< x< 7,143\)

\(\Rightarrow x=6;7\)

Vậy x: 6 hoặc 7