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Topic: quadratic formula
Replies: 5   Last Post: Oct 21, 2012 11:06 AM

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justlooking for someone else

Posts: 77
Registered: 12/10/04
Re: quadratic formula
Posted: Oct 21, 2012 11:06 AM
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Thank you for your explanation, Frederick. You are correct in how I
should have interpreted that question in the first place. I re-read
the question and came to the conclusion that you did. I reviewed the
wiki on completing the square and that was the clue to the required
solution. Appreciate your time and insight into that problem. Thanks


On Thu, 18 Oct 2012 14:13:38 +0100, Frederick Williams
<freddywilliams@btinternet.com> wrote:

>stoneboy wrote:
>> my apologies. I should have used spaces for clarity. add to that I
>> made a typo. darn it. sorry to waste your time folks.
>> if p(x) = ax^2 + bx + c is a second degree polynomial, then
>> prove
>> p(x) = a(x+b/2a)^2 - ( (b^2 - 4ac) / 4a )
>> funny how they want me to derive the latter from the former. Guess I
>> am a little lost.

>It seems to be an odd question. To prove that the second expression for
>p(x) is equal to the first, just multiply out the RHS of the second
>expression. Far more sensible is to ask: given 'ax^2 + bx + c' how does
>one get 'a(x+b/2a)^2 - ((b^2 - 4ac)/(4a))'? The answer to that is 'by
>completing the square'. See
>http://en.wikipedia.org/wiki/Completing_the_square, for example.

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