Question

determine as coordenadas do vértice das funções dadas por:
A) y=x2-4x-5
B) y=-x2 +2x-8

Answer 1

a) x^2-4x-5=0
▲=b^2-4ac
▲=(-4)^2-4.1.(-5)
▲=16+20
▲=36
xv=-b/2a
xv=-(-4)/2.1
xv=4/2
xv=2
yv=-▲/4a
yv=-36/4.1
yv=-36/4
yv=-9
b) -x^2+2x-8=0
▲=b^2-4ac
▲=2^2-4.(-1).(-8)
▲=4-32
▲=-28
xv=-b/2a
xv=-2/2.(-1)
xv=-2/-2
xv=1
yv=-▲/4a
yv=-(-28)/4.(-1)
yv=28/-4
yv=-7