Question

Encontre as coordenadas do vértice Y= -x2 -8x +7

Answer 1

a=-1 b=-8 c=7

Δ=b²-4ac
Δ=(-8)²-4*(-1)*7
Δ= 64+28
Δ=92



Xv= -b/2a 
Xv= -(-8)/2*(-1)
Xv= 8/-2
Xv= -4
      

Yv= -Δ/4a
Yv= -92/4*(-1)
Yv=-92/-4
Yv= 23