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View attachment 79891gíup mình câu 11,12,13,14 với
11. $(\sqrt{20} - 2\sqrt{10} + \sqrt 5). \sqrt 5 +5\sqrt 8=10-10\sqrt 2+5+10\sqrt 2=15$.
12. $(2\sqrt 3-3\sqrt 2)^2+2\sqrt 6+3\sqrt{24} = 12-12\sqrt 6+18+2\sqrt 6+6\sqrt 6=30-4\sqrt 6$.
13. $(\dfrac{\sqrt{14}-\sqrt 7}{1-\sqrt 2}+\dfrac{\sqrt{15}-\sqrt 5}{1-\sqrt 3}):\dfrac1{\sqrt 7-\sqrt 5}$
$=-\left [\dfrac{\sqrt 7(1-\sqrt 2)}{1-\sqrt 2}+\dfrac{\sqrt 5(1-\sqrt 3)}{1-\sqrt 3} \right ].(\sqrt 7-\sqrt 5)$
$=-(\sqrt 7+\sqrt 5)(\sqrt 7-\sqrt 5)=-2$
14. $\dfrac{\sqrt{5+2\sqrt 6}+\sqrt{8-2\sqrt{15}}}{\sqrt{7}+2\sqrt{10}}=\dfrac{\sqrt{(\sqrt{3}+\sqrt{2})^2}+\sqrt{(\sqrt{5}-\sqrt{3})^2}}{\sqrt{7}+2\sqrt{10}}$
$=\dfrac{\sqrt{3}+\sqrt{2}+\sqrt{5}-\sqrt{3}}{\sqrt{7}+2\sqrt{10}}=\dfrac{\sqrt{2}+\sqrt{5}}{\sqrt{7}+2\sqrt{10}}= \dots$
[TẶNG BẠN] TRỌN BỘ Bí kíp học tốt 08 môn
gíup mình câu 11,12,13,14 với
