1. Вычислите: \((\sqrt{72}-\sqrt{50})\cdot7\sqrt{2}\)

\(\sqrt{72}=6\sqrt{2}\), \(\sqrt{50}=5\sqrt{2}\).

\[(6\sqrt{2}-5\sqrt{2})\cdot7\sqrt{2}=\sqrt{2}\cdot7\sqrt{2}=7\cdot2=14.\]

Ответ: 14.