Thực hiện phép tính 9) $$\frac{2x-3y}{2y}$$ + $$\frac{3x-3y}{4xy}$$ . $$\frac{2xy}{y-x}$$ 10) $$\frac{5x+1}{2x-6}$$ + $$\frac{2x+2}{9-x^2}$$ . $$\frac{12+4x}{x+1}$$ 11) $$\frac{14x+19}{10x-15}$$ + $$\frac{4y+4x}{3x-2xy}$$ . $$\frac{2y}{x+y}$$