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  • Usuário do Brainly
2014-05-31T00:01:57-03:00


x1-x2=10                          x1+x2=-b/a

                                         x1+x2=2k

substituição(isola o x1)

x1=10-x2                              10+x2=2k

x1=10-(2k-10                            x2=2k-10

x1=10-2k+10

x1=20-2k                                            


como x1-x2=10  vamos substituir

      20-2k-(2k-10)=10

       20-2k-2k+10=10

                    -4k=10-10-20

                     -4k=-20

                         k=20/4

                          k=5



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