Răspuns:
[tex]2)a)3 \sqrt{7} + 2 \sqrt{7} + 10 \sqrt{7} = 5 \sqrt{7} + 10 \sqrt{7} = 15 \sqrt{7} \\ b)8 \sqrt{2} + 12 \sqrt{2} + 3 \sqrt{2} = 20 \sqrt{2} + 3 \sqrt{2} = 23 \sqrt{2} \\ c)10 \sqrt{5} - 3 \sqrt{5} + 2 \sqrt{5} = 7 \sqrt{5} + 2 \sqrt{5} = 9 \sqrt{5} \\d) - 3 \sqrt{3} + 8 \sqrt{3} + 6 \sqrt{3} - 9 \sqrt{3} = 5 \sqrt{3} + 6 \sqrt{3} - 9 \sqrt{3} = 11 \sqrt{3} - 9 \sqrt{3} = 2 \sqrt{3} [/tex]
[tex]3)a)3 \sqrt{11} + ( - 2 \sqrt{11} + 9 \sqrt{11} ) - 10 \sqrt{11} = 3 \sqrt{11} + 7 \sqrt{11} - 10 \sqrt{11} = 10 \sqrt{11} - 10 \sqrt{11} = 0[/tex]
[tex]b)2 \sqrt{2} - (3 \sqrt{2} - 6 \sqrt{2} + \sqrt{2} ) - \sqrt{2} = 2 \sqrt{2} - ( - 3 \sqrt{2} + \sqrt{2} ) - \sqrt{2} = 2 \sqrt{2} - ( - 2 \sqrt{2} ) - \sqrt{2} = 2 \sqrt{2} + 2 \sqrt{2} - \sqrt{2} = 4 \sqrt{2} - \sqrt{2} = 3 \sqrt{2} [/tex]
[tex]c)(20 \sqrt{6} + 12 \sqrt{6} ) - (4 \sqrt{6} - 2 \sqrt{6} ) = 32 \sqrt{6} - 2 \sqrt{6} = 30 \sqrt{6} [/tex]
[tex]d)(33 \sqrt{7} - 50 \sqrt{7} ) + ( - 3 \sqrt{7} - 5 \sqrt{7} + \sqrt{7} ) = - 17 \sqrt{7} + ( - 8 \sqrt{7} + \sqrt{7} ) = - 17 \sqrt{7} + ( - 7 \sqrt{7} ) = - 17 \sqrt{7} - 7 \sqrt{7} = - 24 \sqrt{7} [/tex]
