You are given the quadratic function
y = x² - 8x + 22
To find the vertex, change the given equation into the form
y = a(x - h)² + k
Where
a = is a constant
(h,k) is the vertex
Thus,
y = x² - 8x + 22
We complete the square, by squaring the half of the coefficient of x (which is -8, the half of -8 is -4, and the square of -4 is 16.) Thus,
y = x² - 8x + 16 + 6
Now, we can factor
y = (x - 4)² + 6
Therefore, the vertex is
(4,6)
^_^
2006-11-27 22:38:19
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answer #1
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answered by kevin! 5
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To calculate the vertex, you have to complete the square:
y = x^2 - 8x + 22
That means you have to take the coefficient of x (which is -8), take half of that, and then square it. So half of -8 is -4, squared is +16. You want to add 16 and subtract 16 (which is, effectively, adding zero and not changing the equation). So now we have
y = x^2 - 8x + 16 + 22 - 16
Now that we have added the "half-squared" of the coefficient of x, the first three terms of the polynomial should be a perfect square. It becomes:
y = (x - 4)^2 + 22 - 16
or
y = (x - 4)^2 + 6
To get the coordinates of the vertex, you take the negative of the term in the brackets, and the whole number outside of the brackets. In this case, it's (- (-2),6), or (2,6).
So the vertex is (2,6)
2006-11-27 18:00:48
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answer #2
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answered by Welgar 2
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the vertex of the equation will be the point at which the parabola has a maximum or minimum depending of the concavity. to find this point take the first derivative and set it to zero. 2x -8 = 0. x= 4. plug this into the original eqn and you get y= 6. vertex = (4, 6)
2006-11-27 18:01:31
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answer #3
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answered by Mike 2
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y' = 2x-8 = 0
2x = 8
x = 4
y(4) = 16-32+22 = 6
Vertex: (4, 6)
2006-11-27 18:06:21
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answer #4
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answered by csp 2
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y' = 2x-8 = 0
2x = 8
x = 4
y(4) = 16-32+22 = 6
Vertex: (4, 6)
2006-11-27 18:00:16
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answer #5
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answered by jacinablackbox 4
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it has lots of answers.for each x ,you have an answer to y.
2006-11-27 19:13:03
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answer #6
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answered by ghsalamatbashi2000 2
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(4,6)
2006-11-27 18:01:30
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answer #7
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answered by che_karlos 2
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(4,6)
2006-11-27 18:00:12
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answer #8
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answered by KT 2
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