Сократите дробь: a) $$rac{3a+12b}{6ab}$$; б) $$rac{15b-20c}{10b}$$; в) $$rac{2a-4}{3(a-2)}$$; г) $$rac{5x(y+2)}{6y+12}$$; д) $$rac{a-5b}{a^2-3ab}$$; e) $$rac{3x^2+15xy}{x+5y}$$.

a) $$rac{3a+12b}{6ab} = rac{3(a+4b)}{6ab} = rac{a+4b}{2ab}$$

б) $$rac{15b-20c}{10b} = rac{5(3b-4c)}{10b} = rac{3b-4c}{2b}$$

в) $$rac{2a-4}{3(a-2)} = rac{2(a-2)}{3(a-2)} = rac{2}{3}$$

г) $$rac{5x(y+2)}{6y+12} = rac{5x(y+2)}{6(y+2)} = rac{5x}{6}$$

д) $$rac{a-5b}{a^2-3ab}$$ - дробь не сокращается.

e) $$rac{3x^2+15xy}{x+5y} = rac{3x(x+5y)}{x+5y} = 3x$$