3. Вычислите $$\sqrt{12} \cdot (\sqrt{3} + \sqrt{12})$$

$$\sqrt{12} \cdot (\sqrt{3} + \sqrt{12}) = \sqrt{12} \cdot \sqrt{3} + \sqrt{12} \cdot \sqrt{12} = \sqrt{12 \cdot 3} + 12 = \sqrt{36} + 12 = 6 + 12 = 18$$ Ответ: 18