Respostas

  • Usuário do Brainly
2014-08-22T01:03:04-03:00
2014-08-22T01:08:03-03:00
2x(4x-1)=21
2x.4x-2x=21
8x²-2x-21=0

∆=(-2)²-4.8.(-21)
∆=4+32.21
∆=4+672
∆=676

x'=[-(-2)+√676]/2.8=[2+26]/16=28/16=14/8=7/4
x''=[-(-2)-√676]/2.8=[2-26]/16=-24/16=-12/8=-6/4=-3/2

S={-3/2,7/4}
2 5 2