2) a²-2ab a²b+3ab²; a²+3ab a²-2a²b'

2) $$\frac{a^2 - 2ab}{a^2 + 3ab} \cdot \frac{a^2b + 3ab^2}{a^3 - 2a^2b} = \frac{a(a-2b) \cdot ab(a+3b)}{a(a+3b) \cdot a^2(a-2b)} = \frac{a^2b(a-2b)(a+3b)}{a^3(a+3b)(a-2b)} = \frac{b}{a}$$

Ответ: $$\frac{b}{a}$$