Phép cộng phân số (tiếp theo)

\(\dfrac{1}{4}< x< \dfrac{2}{5}\)

=>\(\dfrac{5}{20}< x< \dfrac{8}{20}\)

\(\Rightarrow x\in\left\{\dfrac{6}{20};\dfrac{7}{20}\right\}\)

Vậy \(x\in\left\{\dfrac{6}{20};\dfrac{7}{20}\right\}\)

Chúc bn học tốt

\(\dfrac{1}{4}< a,b< \dfrac{2}{5}\)

\(\Leftrightarrow\dfrac{5}{20}< a,b< \dfrac{8}{20}\)

\(\Rightarrow a=\dfrac{6}{20}=\dfrac{3}{10}\\ ,b=\dfrac{7}{20}\)

\(\dfrac{1}{4}< \dfrac{3}{10}< \dfrac{7}{20}< \dfrac{2}{5}\)