20.
[tex]\sqrt[3]{24} + \sqrt[3]{375} = \sqrt[3]{8\cdot3} +\sqrt[3]{125\cdot3} = \sqrt[3]{8}\cdot\sqrt[3]{3}+\sqrt[3]{125}\cdot\sqrt[3]{3} = 2\sqrt[3]{3}+5\sqrt[3]{3} = 7\sqrt[3]{3}[/tex]
21.
[tex]4\sqrt{3} = \sqrt{4^{2}\cdot3} = \sqrt{16\cdot3} = \sqrt{48}[/tex]
22.
[tex]3\sqrt[3]{2} = \sqrt[3]{3^{3}\cdot2} = \sqrt[3]{27\cdot2} = \sqrt[3]{54}[/tex]
