Resposta:
-[tex]x^{2}[/tex]+2x-1=0
a= - 1
b= 2
c= -1
Logo,
Δ = [tex]b^{2}[/tex]-4ac
= [tex]2^{2}[/tex]-4.(-1).(-1)
= 4-4
Δ=0
============
x1= [tex]\frac{-b+ raiz de delta}{2.a}[/tex]
x1 = -2+0/2.(-1)
x1 = 1
===========
x2=[tex]\frac{-b- raiz de delta}{2.a}[/tex]
x2= -2-0/2(-1)
x2=1
