a) \(\frac{75b^5c^3}{50b^4c^4} = \frac{25b^4c^3 \cdot 3b}{25b^4c^3 \cdot 2c} = \frac{3b}{2c}\)
б) \(\frac{2b}{b^2-9b} = \frac{2b}{b(b-9)} = \frac{2}{b-9}\)
в) \(\frac{7x-7y}{x^2-y^2} = \frac{7(x-y)}{(x-y)(x+y)} = \frac{7}{x+y}\)
Ответ: a) \(\frac{3b}{2c}\); б) \(\frac{2}{b-9}\); в) \(\frac{7}{x+y}\)