15) \( \sqrt{72} + \sqrt{8} - 8\sqrt{2} + 2 \)

Решение:

15) \( \sqrt{72} + \sqrt{8} - 8\sqrt{2} + 2 = \sqrt{36 \cdot 2} + \sqrt{4 \cdot 2} - 8\sqrt{2} + 2 = 6\sqrt{2} + 2\sqrt{2} - 8\sqrt{2} + 2 = (6+2-8)\sqrt{2} + 2 = 0\sqrt{2} + 2 = 2 \)

Ответ: 2