bài 1: chứng minh
a, (3+\(\sqrt{5}\))(3-\(\sqrt{5}\))-(2+\(\sqrt{3}\))(2-\(\sqrt{3}\))=3
b, 2\(\sqrt{3}\)(\(\sqrt{2}-5\))+(\(\sqrt{2}-\sqrt{3^2}\))+6\(\sqrt{3}\)=5
c,( \(\sqrt{\frac{4}{3}}-\sqrt{3}+\sqrt{\frac{25}{3}}\)).\(\sqrt{12}\)
d, (1+\(\sqrt{3}-\sqrt{2}\))(1+\(\sqrt{3}+\sqrt{2}\))
bài 2: thực hiện phép tính
a, (\(\sqrt{125}+\sqrt{245}-\sqrt{5}\));\(\sqrt{5}\)
b, (\(\frac{1}{7}-\sqrt{\frac{16}{7}+\sqrt{7}}\)): \(\sqrt{7}\)
bài 6: rút gọn các biểu thức sau
a, A= \(\sqrt{21+6\sqrt{6}}\) + \(\sqrt{26-6\sqrt{6}}\)
b, B= \(\sqrt{7-4\sqrt{3}}\) - \(\sqrt{7+4\sqrt{3}}\)
c, C= \(\sqrt{4+\sqrt{7}}\) - \(\sqrt{4-\sqrt{7}}\)
d, D= \(\sqrt{2+\sqrt{3}}\) + \(\sqrt{14-5\sqrt{3}}\) + \(\sqrt{2}\)
