B) y^2-9/27y^2 * 9y/y-3 ;

B) $$\frac{y^2-9}{27y^2} \cdot \frac{9y}{y-3} = \frac{(y-3)(y+3)}{27y^2} \cdot \frac{9y}{(y-3)} = \frac{9y(y-3)(y+3)}{27y^2(y-3)} = \frac{y+3}{3y}$$

Ответ: $$\frac{y+3}{3y}$$