Respostas

  • Usuário do Brainly
2014-08-12T00:21:44-03:00
X²-x-5=0
Δ=1+20
Δ=21
√Δ= ± √21

x'= \frac{1+ \sqrt{21} }{2}

x"= \frac{1- \sqrt{21} }{2}

Calculando
 \frac{ x^{'} }{ x^{"} } + \frac{ x^{"} }{ x^{'} } =

( \frac{1+ \sqrt{21} }{2} : \frac{1- \sqrt{21} }{2} )+( \frac{1- \sqrt{21} }{2} : \frac{1+ \sqrt{21} }{2} )=

( \frac{1+ \sqrt{21} }{2} . \frac{2}{1- \sqrt{21} } )+( \frac{1-  \sqrt{21} }{2} . \frac{2}{1+ \sqrt{21} } )=

 \frac{1+ \sqrt{21} }{1- \sqrt{21} } + \frac{1- \sqrt{21} }{1+ \sqrt{21} }=

 \frac{(1+ \sqrt{21  } ) ^{2}+(1- \sqrt{21}) ^{2}   }{(1- \sqrt{21})(1+ \sqrt{21} ) } =

  \frac{1+2 \sqrt{21}+21+1-2 \sqrt{21}+21  }{1-21} =

= \frac{44}{-20} =- \frac{44}{20} =- \frac{11}{5}
Obg pela resoluçao e resposta !
Valeu!!!