1) $$5\sqrt{2} - 4\sqrt{8} + 3\sqrt{32} = 5\sqrt{2} - 4\sqrt{4 \cdot 2} + 3\sqrt{16 \cdot 2} = 5\sqrt{2} - 4 \cdot 2\sqrt{2} + 3 \cdot 4\sqrt{2} = 5\sqrt{2} - 8\sqrt{2} + 12\sqrt{2} = (5 - 8 + 12)\sqrt{2} = 9\sqrt{2}$$
Ответ: $$9\sqrt{2}$$