Răspuns:
[tex]( - 7 \sqrt{14} \div ( - \sqrt{2)} - \sqrt{28} + \sqrt{63} \times (2 - \sqrt{7)} [/tex]
[tex] = (7 \sqrt{7} - \sqrt{28} + \sqrt{63} \times (2 - \sqrt{7} )[/tex]
[tex] = 7 \sqrt{7} - 2 \sqrt{7} + 3 \sqrt{7} \times (2 - \sqrt{7} )[/tex]
[tex] = 7 \sqrt{7} - 2 \sqrt{7} + 6 \sqrt{7} - 21[/tex]
[tex] = 11 \sqrt{7} - 21[/tex]
