For f(x) = -2x^2 - 8x-2

a. Determine whether the parabola opens up or down

b. Find the vertex

how can determine whether the parabola opens up or down and find the vertex? Thanks in advance.

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- Dec 10th 2012, 02:31 PMmaiden129Porabola and Vertex
For f(x) = -2x^2 - 8x-2

a. Determine whether the parabola opens up or down

b. Find the vertex

how can determine whether the parabola opens up or down and find the vertex? Thanks in advance. - Dec 10th 2012, 02:46 PMskeeterRe: Porabola and Vertex
$\displaystyle f(x) = ax^2 + bx + c$

if the leading coefficient, $\displaystyle a$ , of the quadratic is positive, the parabola opens upward

if the leading coefficient, $\displaystyle a$ , of the quadratic is negative, the parabola opens downward

the x-value of the vertex is $\displaystyle x = \frac{-b}{2a}$ - Dec 10th 2012, 03:04 PMsakonpure6Re: Porabola and Vertex
It opens down because a is negative as skeeter mentioned as as for the vertex, I also can assume you have not learned how to do vertex form? because the equation you provided does not factor.

- Dec 10th 2012, 03:10 PMskeeterRe: Porabola and Vertex
- Dec 10th 2012, 03:11 PMsakonpure6Re: Porabola and Vertex