50. Сократите дробь: \(\frac{5x-15y}{x^2-9y^2}\)

\(5x-15y=5(x-3y)\), \(x^2-9y^2=(x-3y)(x+3y)\).

\(\frac{5(x-3y)}{(x-3y)(x+3y)}=\frac{5}{x+3y}\).

Ответ: \(\frac{5}{x+3y}\)