Răspuns:
[tex]3 \sqrt{5} = \sqrt{ {3 }^{2} \times 5 } = \sqrt{9 \times 5} = \sqrt{45} [/tex]
[tex]5 \sqrt{3} = \sqrt{ {5}^{2} \times 3} = \sqrt{25 \times 3} = \sqrt{75} [/tex]
[tex]2 \sqrt{7} = \sqrt{28} \\ 3 \sqrt{2} = \sqrt{18} \\ 2 \sqrt{7} - 3 \sqrt{2} = \sqrt{28} - \sqrt{18} [/tex]