Answer:
[tex]y = a {x }^{2} + bx + c \\ max \: or \: min \: point \\ x = \frac{ - b}{2a} = \frac{ - 8}{4} = - 2 \\ y = 2 \times {( - 2)}^{2} + 8 \times ( - 2) - 4 = 8 - 16 - 4 = - 12[/tex]
