x/3=y/7 và x+y=20
=> \(\frac{x}{3}=\frac{y}{7}\Rightarrow\frac{x+y}{3+7}=\frac{20}{10}=2\)
\(\Rightarrow x=2.3=6\)
\(\Rightarrow y=2.7=14\)
\(\frac{x}{3}\)= \(\frac{y}{7}\)= \(\frac{x+y}{3+7}\)= \(\frac{20}{10}\)= \(2\)
Ta có: \(\frac{x}{3}\)= 2 => \(x\) = 6
\(\frac{y}{7}\)= 2 => \(y\)= 14