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