Question

rút gọn K

K = \(\sqrt{9-\sqrt{17}}.\sqrt{9+\sqrt{17}}-\sqrt{\left(-8\right)^2}\)

Answer 1

\(K=\sqrt{9-\sqrt{17}}\cdot\sqrt{9+\sqrt{17}}-\sqrt{\left(-8\right)^2}\)

    \(=\sqrt{\left(9-\sqrt{17}\right)\left(9+\sqrt{17}\right)}-\sqrt{\left(-8\right)^2}\)

    \(=\sqrt{81-17}-8=\sqrt{64}-8=8-8=0\)

Answer 2

\(=\sqrt{81-17}-8\)

=8-8

=0