Câu trả lời:
13) \(\sqrt{27+10\sqrt{2}}=\sqrt{5^2+2.5\sqrt{2}+(\sqrt{2})^2}=\sqrt{(5+\sqrt{2})^2}=5+\sqrt{2}\)
14,15) \(\sqrt{11+6\sqrt{2}}=\sqrt{3^2+2.3\sqrt{2}+(\sqrt{3})^2}=\sqrt{(3+\sqrt{2})^2}=3+\sqrt{2}\)
16) \(\sqrt{28+10\sqrt{3}}=\sqrt{5^2+2.5.\sqrt{3}+(\sqrt{3})^2}=\sqrt{(5+\sqrt{3})^2}=5+\sqrt{3}\)
17) \(\sqrt{11-4\sqrt{7}}=\sqrt{2^2-2.2.\sqrt{7}+(\sqrt{7})^2}=\sqrt{(2-\sqrt{7})^2}=2-\sqrt{7}\)