Question

tìm y

y/15 < 4/45  

25/13 <5/y                {y>0}

Answer 1

\(\dfrac{y}{15}< \dfrac{4}{45}\)

\(\dfrac{y\times3}{15\times3}< \dfrac{4}{45}\)

\(\dfrac{y\times3}{45}< \dfrac{4}{45}\)

\(\Rightarrow y\times3< 4\)

\(y< \dfrac{4}{3}\)

\(\dfrac{25}{13}< \dfrac{5}{y}\)

\(\dfrac{25}{13}< \dfrac{5\times5}{y\times5}\)

\(\dfrac{25}{13}< \dfrac{25}{y\times5}\)

\(\Rightarrow y\times5< 13\)

\(y< \dfrac{13}{5}\)