Question

calcule o vertice da parabola: y=x2+2x-y

Answer 1

y=x²+2x-y=0   /a=1 b= 2 c=-1
xv=-b/2.a  xv=-2/2.1 xv=-1

yv= -delta/4.a 
yv=-(b²-4ac)/4a
yv=-(2²-4.1.(-1))/4
yv= -8/4
yv=-2

Vértice=(-1,-2)

espero ter ajudado ...