Question

Tìm x thuộc N,biết

\(\frac{5}{8}< \frac{4}{x}< \frac{5}{7}\)

GIÚP MIK VỚI!!!!!!!!!!!!!!!!!!!!!

Answer 1

\(\frac{5}{8}< \frac{4}{x}< \frac{5}{7}\)

\(\frac{5}{8}\cdot\frac{4}{4}< \frac{4}{x}\cdot\frac{5}{5}< \frac{5}{7}\cdot\frac{4}{4}\)

\(\frac{20}{32}< \frac{20}{5x}< \frac{20}{28}\)

\(\Rightarrow\frac{20}{32}< \frac{20}{30}< \frac{20}{28}\)

\(5x=30\)

\(x=6\)