Muốn so sánh đc phải quy đồng:
\(\frac{4}{5}=\frac{4.7}{5.7}=\frac{28}{35}\)
\(\frac{2}{7}=\frac{2.5}{7.5}=\frac{10}{35}\)
VÌ \(\frac{28}{35}\)>\(\frac{10}{35}\)
\(\rightarrow\)\(\frac{4}{5}\)>\(\frac{2}{7}\)
4/5 = 28/35
2/7 = 10/35
Vì 28/35 > 10/35 => 4/5 > 2/7
Vậy 4/5 > 2/7
\(\frac{4}{5}\)=\(\frac{4\times7}{5\times7}\)=\(\frac{28}{35}\)
\(\frac{2}{7}\)=\(\frac{2\times5}{5\times7}\)=\(\frac{10}{37}\)
\(Vì\) \(28>10\)\(Nên\) \(\frac{28}{35}\)\(>\frac{10}{35}\)
\(\Rightarrow\frac{4}{5}\)\(>\frac{2}{7}\)