Question

chứng minh căn 9-căn 17 . căn 9+căn 17=8

Answer 1

\(\sqrt{9-\sqrt{17}}\cdot\sqrt{9+\sqrt{17}}=\sqrt{\left(9-\sqrt{17}\right)\left(9+\sqrt{17}\right)}=\sqrt{9^2-\left(\sqrt{17}\right)^2}=\sqrt{81-17}\)

\(=\sqrt{64}=8.\)

Answer 2

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Answer 3

Chứng minh

a)√(9+√17)+√(9-√17)=√34

b)√(8+√15)+√(8-√15)=√30