SOLUTION: find the vertex of the parabola y = -4x2 - 16x - 11

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Question 530685: find the vertex of the parabola y = -4x2 - 16x - 11
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
The x-coordinate of the vertex can be found by:
x+=+%28-b%29%2F2a where: a = -4 and b = -16.
x+=+%28-%28-16%29%29%2F2%28-4%29 Evaluate.
x+=+16%2F%28-8%29
x+=+-2 Now substitute this value of x into the given quadratic equation to find the value of the y-coordinate.
y+=+-4%28-2%5E2%29-16%28-2%29-11 Evaluate.
y+=+-16%2B32-11
y+=+5
The vertex is at (-2,5)
Here's the graph:
graph%28400%2C400%2C-5%2C5%2C-5%2C10%2C-4x%5E2-16x-11%29