Question

What is the vertex, axis of symmetry, the maximum or minimum value, and the range of parabola `y=-2x^2-8x+3`?

Answer 1

Vertex (x, y)
x of vertex and axis of symmetry: x = -b/2a = 8/-4 = -2.
y of vertex: y = f(-2) = -8 + 16 + 3 = 11
The vertex is a Max because the parabola opens downward (a negative).
Find x- intercepts by makingy = 0

`D = d^2 = b^2 - 4ac = 64 + 24 = 88 -> d = +-2sqrt22`
`x = -2 +-2sqrt22/-4 = -2 +- sqrt22/2`