Answer:
Step-by-step explanation:
[tex]\frac{a+b}{a-b} =\frac{2}{1} \\by ~componendo~and~dividendo\\\\\frac{(a+b)+(a-b)}{(a+b)_(a-b)} =\frac{2+1}{2-1} \\\frac{a+b+a-b}{a+b-a+b} =3\\\frac{2a}{2b} =3\\\frac{a}{b} =3\\a:b::2:1[/tex]
