Respostas

2014-05-25T17:58:57-03:00
Encontrando o Xv...
y= x²-6x+8 a=1 b=-6 c=8
Xv= -b/2a -> -(-6)/2x1 -> Xv= 6/2= 3
Substituindo para encontrar o Yv ...
y=x²-6x+8
y= 3²-6x3+8
y= 9-18+8
Yv= -1

Δ=b²-4ac= (-6)²-4x1x8= 36-32= 4

BHASKÁRA
x=-b+-√Δ/2a
x'= 6+2/2= 4
x''= 6-2/2= 2