Question

(D) S={(-3, -6), (-39, 12)
4) O vértice da parábola que representa a função y = x2 – 2x – 8 é:
(A) V = (1, -9)
(B) V = (1,9)
(C) V = (- 1,-9)
(D) V = (0, -9
.....​

Answer 1

Resposta:

$\sf \: ∆ = b {}^{2} - 4ac = ( - 2) {}^{2} - 4.1.( - 8) = 4 + 32 = \color{red}{}36$

$\sf \:xv = -b/2a = 2/2.1 = 2/2 =\color{red}{} 1$

$\sf \:yv = -∆/4a = -36/4 =\color{red}{} -9$

$\color{red}{}\sf \:a) \: 1 \: e \: -9$