Сократите дробь: a) $$rac{y^2-16}{3y+12}$$; б) $$rac{5x-15y}{x^2-9y^2}$$; в) $$rac{(c+2)^2}{7c^2+14c}$$; г) $$rac{6cd-18c}{(d-3)^2}$$; д) $$rac{a^2+10a+25}{a^2-25}$$; e) $$rac{y^2-9}{y^2-6y+9}$$.

a) $$rac{y^2-16}{3y+12} = rac{(y-4)(y+4)}{3(y+4)} = rac{y-4}{3}$$

б) $$rac{5x-15y}{x^2-9y^2} = rac{5(x-3y)}{(x-3y)(x+3y)} = rac{5}{x+3y}$$

в) $$rac{(c+2)^2}{7c^2+14c} = rac{(c+2)(c+2)}{7c(c+2)} = rac{c+2}{7c}$$

г) $$rac{6cd-18c}{(d-3)^2} = rac{6c(d-3)}{(d-3)(d-3)} = rac{6c}{d-3}$$

д) $$rac{a^2+10a+25}{a^2-25} = rac{(a+5)^2}{(a-5)(a+5)} = rac{a+5}{a-5}$$

e) $$rac{y^2-9}{y^2-6y+9} = rac{(y-3)(y+3)}{(y-3)^2} = rac{y+3}{y-3}$$