Vì \(\frac{5a+7b}{6a+5b}=\frac{28}{29}\)
\(\Rightarrow\left(5a+7b\right).28=\left(6a+5b\right).29\)
\(\Rightarrow140a+196b=174a+145b\)
\(\Rightarrow\)\(51b=34a\)
\(\Rightarrow\)\(a=51;b=34\)
ta co 5a + 7b = 29 va 6a + 5b +28
giai hpt ta dc a = 3 và b= 2