1) \(\left(3 - \frac{x+y}{x-y}\right) : \left(\frac{3x}{x+y} - 2\right)\) 2) \(\left(\frac{9a-3b}{a+b} - 1\right) : \left(3 + \frac{a+b}{a-b}\right)\)

Решение:

1. 1) \( \left(3 - \frac{x+y}{x-y}\right) : \left(\frac{3x}{x+y} - 2\right) = \left(\frac{3(x-y) - (x+y)}{x-y}\right) : \left(\frac{3x - 2(x+y)}{x+y}\right) = \left(\frac{3x-3y-x-y}{x-y}\right) : \left(\frac{3x-2x-2y}{x+y}\right) = \left(\frac{2x-4y}{x-y}\right) : \left(\frac{x-2y}{x+y}\right) = \frac{2(x-2y)}{x-y} \cdot \frac{x+y}{x-2y} = \frac{2(x+y)}{x-y} \)
2. 2) \( \left(\frac{9a-3b}{a+b} - 1\right) : \left(3 + \frac{a+b}{a-b}\right) = \left(\frac{9a-3b - (a+b)}{a+b}\right) : \left(\frac{3(a-b) + (a+b)}{a-b}\right) = \left(\frac{9a-3b-a-b}{a+b}\right) : \left(\frac{3a-3b+a+b}{a-b}\right) = \left(\frac{8a-4b}{a+b}\right) : \left(\frac{4a-2b}{a-b}\right) = \frac{4(2a-b)}{a+b} \cdot \frac{a-b}{2(2a-b)} = \frac{2(a-b)}{a+b} \)

Ответ: 1) \(\frac{2(x+y)}{x-y}\); 2) \(\frac{2(a-b)}{a+b}\).