Ответ:\(\frac{\sqrt{21}\cdot\sqrt{14}}{\sqrt{6}}=\sqrt{\frac{21\cdot14}{6}}=\sqrt{49}=7\).\(\frac{\sqrt{35}\cdot\sqrt{21}}{\sqrt{15}}=\sqrt{\frac{35\cdot21}{15}}=\sqrt{49}=7\).Ответ: 1) 7; 2) 7.