Salutare!
[tex]\bf \dfrac{3a+b}{2a+7b}=\dfrac{1}{5}[/tex]
[tex]\bf 5 \cdot(3a+b)=1\cdot(2a+7b)[/tex]
[tex]\bf 15a+5b=2a+7b[/tex]
[tex]\bf 15a-2a+5b=7b[/tex]
[tex]\bf 13a=7b-5b[/tex]
[tex]\bf 13a=2b[/tex]
[tex]\boxed{\bf \dfrac{a}{b} =\dfrac{2}{13}}[/tex]
Bafta multa !!!
