Question

√17-3√32 -√17+3√32

Answer 1

\(\sqrt{17}-3\sqrt{32}-\sqrt{17}+3\sqrt{32}\\ =\left(\sqrt{17}-\sqrt{17}\right)+\left(3\sqrt{32}-3\sqrt{32}\right)\\ =0+0=0\)

Answer 2

\(=\sqrt{17-12\sqrt{2}}-\sqrt{17+12\sqrt{2}}\)

\(=\sqrt{17-2\cdot3\cdot2\sqrt{2}}-\sqrt{17+2\cdot3\cdot2\sqrt{2}}\)

\(=\sqrt{\left(3-2\sqrt{2}\right)^2}-\sqrt{\left(3+2\sqrt{2}\right)^2}\)

=3-2căn 2-3-2căn 2

=-4căn 2