Respostas

  • Usuário do Brainly
2014-05-25T16:57:10-03:00

x(a quarta)-6x²+9=x²-1

x(quarta0 -7x²+10=1                 x²=y

y²-7y+10=0       Δ= 49-40=9                              x²=5    x= √5 

                                                                                x²=2     x=√2

y=(7+3)/2=10/2=5

y=( 7-3)/2= 2  voltando no x fica                      S= {√2,√5}