Respostas

  • Usuário do Brainly
2014-08-13T18:17:49-03:00
X²-2x-8=0
a=1 b= -2 c= -8
b²-4.a.c
Δ=b²-4.a.c
Δ= (-2)²-4.1(8)
Δ= -4(32)
Δ=36

-b±√Δ¯ = -2±√36 =6/2 =4
2.a

x' 6+2 = 8/4
x'' 2-6 = -4/2 = -2

Então obteremos as raizes : 4 e -2