[tex]2 \sqrt{17} = \sqrt{ {2}^{2} \times 17} = \sqrt{68} [/tex]
[tex]9 = \sqrt{81} [/tex]
[tex] \sqrt{81} > \sqrt{68} = > [/tex]
[tex] | 2\sqrt{17} - 9 | = - 2 \sqrt{17} + 9[/tex]
