Question

O vertice da parabola y=-x2+4x+5 é?

Answer 1

Xv = -b/2a ---> -4/2.(-1) = 2
Yv = -delta/4a
Delta: b^2 - 4ac -> (4)^2 - 4.-1.5 --->16 + 20 ---> 36
então, retomando: -36/4.-1 ----> 9
o vértice é (2,9)

Answer 2

-x²+4+5=0 a=-1 b=4/c=5

Δ=b²-4.a.c
Δ=4²-4.-1.5
Δ=16+4.5
Δ=16+20=36

xv= -b/2a
xv= -4/2.-1
xv=-4/-2
xv=2

yv= -Δ/4a
yv= -36/4.-1
yv=-36/-4
yv=9