Verified answer

Y= x²-2x-4 (a=1 , b=-2 , c=-4)

Yv= -b/2.a = -(-2)/2.1 = 2/2 = 1

Δ= b²-4.a.c

Δ= (-2)² -4.1.(-4)

Δ= 4-4.(-4)

Δ= 4-16

Δ= -12

Yv= -Δ/4.a = -(-12)/4.1 = 12/4 = 3

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Y=-2x² + x-3 (a=-2, b=1 , c=-3)

Xv= -b/2.a = -1/2.(-2) = -1/-4

Δ= b² -4.a.c

Δ= (1)²-4.(-2).(-3)

Δ= 1-8.(-3)

Δ= 1-24

Δ= -23

Yv= -Δ/4.a = -(-23)/4.(-2) = 23/-8

Espero ter ajudado

Boa noite

Abraço

a)

x² - 3x - 4 = 0

delta

d² = 9 + 16 = 25

Vértice

Vx = -b/2a = 3/2

Vy = -d²/4a = -25/4

b)

-2x² + x - 3 = 0

delta

d² = 1 - 24 = -23

Vértice

Vx = -b/2a = -1/-4 = 1/4

Vy = -d²/4a = 23/-8 = -23/8

pronto