Đáp án+Giải thích các bước giải:
$LV7:\\A = \sqrt{4 +\sqrt{5\sqrt{3} + 5\sqrt{48 - 10\sqrt{7+4\sqrt{3}}}}}\\A = \sqrt{4 +\sqrt{5\sqrt{3} + 5\sqrt{48 - 10\sqrt{(2+\sqrt{3})^2}}}}\\A =\sqrt{4 +\sqrt{5\sqrt{3} + 5\sqrt{48 - 10(2+\sqrt{3})}}}\\A =\sqrt{4 +\sqrt{5\sqrt{3} + 5\sqrt{48 - 20 -10\sqrt{3}}}}\\A =\sqrt{4 +\sqrt{5\sqrt{3} + 5\sqrt{28-10\sqrt{3}}}}\\A =\sqrt{4 +\sqrt{5\sqrt{3} + 5\sqrt{(5-\sqrt{3})^2}}} \\A =\sqrt{4 +\sqrt{5\sqrt{3} + 5(5-\sqrt{3})}} \\A =\sqrt{4 +\sqrt{5\sqrt{3} + 25-5\sqrt{3}}}\\A = \sqrt{4+\sqrt{25}}\\A =\sqrt{4+5}\\A=3\\B = \sqrt{2+\sqrt{3}+\sqrt{4-2\sqrt{3}-\sqrt{21-12\sqrt{3}}}}\\B = \sqrt{2+\sqrt{3}+\sqrt{4-2\sqrt{3}-\sqrt{(3-2\sqrt{3})^2}}}\\B =\sqrt{2+\sqrt{3}+\sqrt{4-2\sqrt{3}-(2\sqrt{3}-3)}}\\B = \sqrt{2+\sqrt{3}+\sqrt{7-4\sqrt{3}}}\\B = \sqrt{2+\sqrt{3}+\sqrt{(2-\sqrt{3})^2}}\\B = \sqrt{2+\sqrt{3}+2-\sqrt{3}}\\B = \sqrt{4}=2$