Answer:
a. vertex = (-6, -88); axis of symmetry: x = -6
Step-by-step explanation:
For quadratic y=ax²+bx+c, the axis of symmetry is x=-b/(2a). Here, that is ...
x=-24/(2·2) = -6 . . . . . matches choice A
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If you put the equation into vertex form, or evaluate it for x=-6, or if you use a graphing calculator to plot it, you find the vertex is (-6, -88) . . . . also matches choice A.
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Evaluation:
(2×-6 +24)×-6 -16 = 12×-6 -16 = -72 -16 = -88. . . . . vertex is (-6, -88)
Vertex form:
y=2(x² +12x) -16 = 2(x² +12x +36) -16 -2(36) = 2(x +6)² -88 . . . . vertex is (-6, -88)
