$\color{blue}{\text{[Toán 9] Tính giá trị biểu thức chứa căn bậc hai.}}$

T

toiyeu9a3

$\sqrt{17 - 4\sqrt{9 - 4\sqrt{5}}} = \sqrt{17 - 4(\sqrt{5} - 2} = \sqrt{25 - 4\sqrt{5}}$
 
B

buivanbao123

$\sqrt{17-4 \sqrt{9-4 \sqrt{5}}}$
=$\sqrt{17-4 \sqrt{(\sqrt{5}-2)^{2}}}$
=$\sqrt{17-4(\sqrt{5}-2)}$
=$\sqrt{17-4\sqrt{5}+8}$
=$\sqrt{25-4\sqrt{5}}$
 
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