2) 3√0,09y-0,6 √144y + 18/11 √121/36 y =

$$3\sqrt{0.09y} - 0.6\sqrt{144y} + \frac{18}{11}\sqrt{\frac{121}{36}y} = 3\cdot 0.3\sqrt{y} - 0.6\cdot 12\sqrt{y} + \frac{18}{11}\cdot \frac{11}{6}\sqrt{y} = 0.9\sqrt{y} - 7.2\sqrt{y} + 3\sqrt{y} = (0.9-7.2+3)\sqrt{y} = -3.3\sqrt{y}$$

Ответ: $$-3.3\sqrt{y}$$