Ответ:

[tex]2 \sqrt{5} = \sqrt{ {2}^{2} \times 5 } = \sqrt{4 \times 5} = \sqrt{20} [/tex]

[tex]5 \sqrt{2} = \sqrt{ {5}^{2} \times 2 } = \sqrt{25 \times 2} = \sqrt{50} [/tex]

[tex] \sqrt{20} < \sqrt{50} [/tex]