2.
[tex]a)\\10\sqrt[3]{9}+5\sqrt[3]{9} -12\sqrt[3]{9}=15\sqrt[3]{9}-12\sqrt[3]{9} = 3\sqrt[3]{9}\\\\b)\\ \sqrt{2}+\sqrt{3}-2\sqrt{2}-8\sqrt{3}+9\sqrt{2} - \sqrt{3} = 8\sqrt{2}-8\sqrt{3}\\\\c)\\\sqrt{50}+\sqrt{12}-3\sqrt{18}+\sqrt{4} =\sqrt{25\cdot2}+\sqrt{4\cdot3}-3\sqrt{9\cdot2}+2=\\\\=\sqrt{25}\cdot\sqrt{2}+\sqrt{4}\cdot\sqrt{3} -3\sqrt{9}\cdot\sqrt{2}+2=\\\\=5\sqrt{2}+2\sqrt{3}-9\sqrt{2}+2 = 2+2\sqrt{3}-4\sqrt{2}[/tex]
[tex]d)\\3\sqrt{8}-9\sqrt{16}+2\sqrt{25}-3\sqrt{80} = 3\sqrt{4\cdot2} - 9\cdot4 + 2\cdot5 - 3\sqrt{16\cdot5}=\\\\=3\cdot2\sqrt{2}-36+10-3\cdot4\sqrt{5} = 6\sqrt{2}-26-12\sqrt{5}[/tex]
