Ответ:

1. 7 \(\cdot\) 2 \(\cdot\) \(\sqrt{15}\) \(\cdot\) \(\sqrt{2}\) \(\cdot\) \(\sqrt{2 \cdot 15}\) = 14 \(\cdot\) \(\sqrt{15}\) \(\cdot\) \(\sqrt{2}\) \(\cdot\) \(\sqrt{2}\) \(\cdot\) \(\sqrt{15}\).
2. 14 \(\cdot\) \(\sqrt{15} \cdot \sqrt{15}\) \(\cdot\) \(\sqrt{2} \cdot \sqrt{2}\) = 14 \(\cdot\) 15 \(\cdot\) 2.
3. \(\text{Ответ: }\) 420.