[tex] \sqrt{21 } \times \sqrt{7} + \sqrt{5} \times \sqrt{15} = \\ \sqrt{147} + \sqrt{75} = \\ 7 \sqrt{3} + 5 \sqrt{3} = \\ (7 + 5) \sqrt{3} = \\ 12 \sqrt{3} [/tex]
C
[tex]( - \sqrt{10} ) \times \sqrt{5} + \sqrt{14} \times \sqrt{7} = \\ - \sqrt{10} \times \sqrt{5} + \sqrt{14} \times \sqrt{7} = \\ - \sqrt{50} + \sqrt{14} \times \sqrt{7} = \\ - \sqrt{50} + \sqrt{98} = \\ 5 \sqrt{2} + 7 \sqrt{2} = \\ 2 \sqrt{2} [/tex]
se reduc termeni asemanatori
E
[tex]( - \sqrt{14} ) \times (4 \sqrt{7} ) - (5 \sqrt{6} ) \times ( - \sqrt{3}) = \\ - \sqrt{14} \times 4 \sqrt{7} - (5 \sqrt{6} ) \times ( - \sqrt{3} ) = \\ 4 \sqrt{98} - 5 \sqrt{6} \times ( - \sqrt{3} ) = \\ - 28 \sqrt{2} - 5 \sqrt{6} \times ( - \sqrt{3} ) = \\ - 28 \sqrt{2} + 5 \sqrt{6} \times \sqrt{3} = \\ - 28 \sqrt{2} + 15 \sqrt{2} = \\ - 13 \sqrt{2} [/tex]
G
nu l-am stiu sper ca team ajuta si sa ma respatestu cu o Coroana
