a)
[tex]8 \sqrt{2} + 4( \sqrt{5} - 2 \sqrt{2} ) - 3 \sqrt{5} = 8 \sqrt{2} + 4 \sqrt{5} - 8\sqrt{2} - 3 \sqrt{5} = \sqrt{5} [/tex]
b)
[tex]15 \sqrt{3} - 3 \sqrt{7} - 15 \sqrt{3} - 2 \sqrt{7} = - 5 \sqrt{7} [/tex]
c)
[tex]4 \sqrt{3} + 2 \sqrt{2} - 2 \sqrt{2} - 4 \sqrt{3} = 0[/tex]
d)
[tex]2 \sqrt{6} - 9 - 2 \sqrt{6} +6 = - 3[/tex]
