Răspuns :
[tex]\sqrt{63} -3(2\sqrt{7}-4\sqrt{3})+4(2\sqrt{3}+5\sqrt{7} )=\\3\sqrt{7} -6\sqrt{7} +12\sqrt{3}+8\sqrt{3} +20\sqrt{7} =\\23\sqrt{3} +14\sqrt{7}[/tex]
[tex]\sqrt{63} -3(2\sqrt{7}-4\sqrt{3})+4(2\sqrt{3}+5\sqrt{7} )=\\3\sqrt{7} -6\sqrt{7} +12\sqrt{3}+8\sqrt{3} +20\sqrt{7} =\\23\sqrt{3} +14\sqrt{7}[/tex]