Выполните деление: (a^2-b^2)/(a+3b):(ab+b^2)/(2a+6b).

\[\frac{a^{2} - b^{2}}{a + 3b}\ :\frac{ab + b^{2}}{2a + 6b} =\]

\[= \frac{a^{2} - b^{2}}{a + 3b} \cdot \frac{2a + 6b}{ab + b^{2}} =\]

\[= \frac{(a - b)(a + b) \cdot 2(a + 3b)}{(a + 3b) \cdot b(a + b)} =\]

\[= \frac{2(a - b)}{b} = \frac{2a - 2b}{b}.\]