Răspuns:
[tex]\frac{1}{7-4\sqrt{3} }[/tex]+[tex]\frac{1}{7+4\sqrt{3} }[/tex]=>amplificam [tex]\frac{1}{7-4\sqrt{3} }[/tex] cu 7+[tex]4\sqrt{3}[/tex] si [tex]\frac{1}{7+4\sqrt{3} }[/tex] cu [tex]7-4\sqrt{3}[/tex]
=>[tex]\frac{7+4\sqrt{3} }{7^{2} -4\sqrt{3} ^{2} } }[/tex]+[tex]\frac{7-4\sqrt{3} }{7^{2}-4\sqrt{3} ^{2} }[/tex]=>[tex]\frac{7+4\sqrt{3} }{49-48}[/tex]+[tex]\frac{7-4\sqrt{3} }{49-48}[/tex]=>[tex]\frac{14}{1}[/tex]=14
raspuns: c)Bianca
