Odpowiedź:
[tex]b)\ \ (2\sqrt{5}-4\sqrt{2})(2\sqrt{2}+\sqrt{5})=4\sqrt{10}+2\sqrt{25}-8\sqrt{4}-4\sqrt{10}=2*5-8*2=\\\\=10-16=-6\\\\\\c)\ \ (2\sqrt{3}-3\sqrt{2})(\sqrt{2}+\sqrt{3})-(4-\sqrt{6})=2\sqrt{6}+2\sqrt{9}-3\sqrt{4}-3\sqrt{6}-4+\sqrt{6}=\\\\=3\sqrt{6}-3\sqrt{6}+2*3-3*2-4=6-6-4=-4\\\\\\d)\ \ (\sqrt{5}+2\sqrt{3})(2\sqrt{5}-\sqrt{3})+(6-3\sqrt{15})=2\sqrt{25}-\sqrt{15}+4\sqrt{15}-2\sqrt{9}+6-3\sqrt{15}=\\\\=2*5+3\sqrt{15}-2*3+6-3\sqrt{15}=10-6+6=10[/tex]
