Áp dụng công thức : \(\frac{a}{b}=\frac{c}{d}\) \(\Leftrightarrow ad=bc\)
Ta có :
\(\left(5a+7b\right).28=29.\left(6a+5b\right)\)
\(140a+196b=174a+145b\)
\(51b=34a\)
\(\frac{51}{34}=\frac{a}{b}\)
\(\Leftrightarrow\frac{3}{2}=\frac{a}{b}\)
Vậy a = 3 ; b = 2
\(\Rightarrow28\left(5a+7b\right)=29\left(6a+5b\right)\)
\(\Rightarrow140a+196b=174a+145b\)
\(\Rightarrow196b-145b=174a-140a\)
\(\Rightarrow51b=34a\)
\(\Rightarrow3b=2a\)
=>a=3 b=2
=> 28 ( 5a + 7b ) = 29 ( 6a + 5b )
=> 140a + 196b = 174a + 145b
=> 196b - 195b = 174a - 140a
=> 51b = 34a
=> 51b = 34a
=>3b = 2a
=> a = 3 ; b = 2
