Răspuns:
Explicație pas cu pas:
[tex](2\sqrt{3} +\sqrt{5} ) (3\sqrt{3} -3\sqrt{5} )=\\6*3-6\sqrt{15} +3\sqrt{15}-3*5=\\ 18-3\sqrt{15}-15= 3-3\sqrt{15}[/tex]
([tex](4\sqrt{3} -2\sqrt{7} ) (\sqrt{7} -3\sqrt{3} )=\\4\sqrt{21} -4*3-2*7+6\sqrt{21} =\\10\sqrt{21} -12-14= 10\sqrt{21} -26[/tex]
