Răspuns:
[tex] 2\sqrt{2646} = 2\sqrt{2 \times 3 \times {21}^{2} } = 42 \sqrt{6} [/tex]
[tex]2 \sqrt{1922} = 2 \sqrt{2 \times {31}^{2} } = 62 \sqrt{2} [/tex]
[tex]3 \sqrt{392} = 3 \sqrt{2 \times {14}^{2} } = 42 \sqrt{2} [/tex]
[tex]3 \sqrt{735} = 3 \sqrt{3 \times 5 \times {7}^{2} } = 21 \sqrt{15} [/tex]
[tex]4 \sqrt{2000} = 4\sqrt{ {2}^{4} \times {5}^{3} } = 80 \sqrt{5} [/tex]
[tex]3 \sqrt{1280} = 3 \sqrt{ {2}^{8} \times 5} = 16 \sqrt{5} [/tex]
[tex]42 \sqrt{6} (62 \sqrt{2} - 42 \sqrt{2} ) + 21 \sqrt{15} (80 \sqrt{5} - 16 \sqrt{5} ) = 42 \sqrt{6} \times 20 \sqrt{2} + 21 \sqrt{15} \times 64 \sqrt{5} [/tex]
[tex]168 \sqrt{3} + 6720 \sqrt{3} = 6888 \sqrt{3} [/tex]
