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Express y=x^2+x-12 in the form (x+a)^2-b Watch

    • Thread Starter
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    I've got

    (x-2)^2-12

    but not sure if correct?
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    (Original post by Prefetch)
    I've got

    (x-2)^2-12

    but not sure if correct?
    This is not quite right. If you expand out what you got, you get (x^2-4x+4)-12

    When we have something in the form x^2+dx-e, we can write it in the form (x+a)^2-b by letting a=\frac{d}{2} and then -b=-(\frac{d}{2})^2-e.

    So can you follow this to get the right answer?
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    Thanks.

    I think the answer is

    (x+0.5)^2 - 12.25
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    (Original post by Prefetch)
    Thanks.

    I think the answer is

    (x+0.5)^2 - 12.25
    That's right!
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    (x+0.5)^2 - 12.25

    Complete the square!
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    (Original post by Mike173)
    (x+0.5)^2 - 12.25

    Complete the square!
    Please clarify?
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    (Original post by Prefetch)
    Please clarify?
    Completing the square is the process of converting an expression of the form  cx^2 + dx + e into the form  c(x+a)^2 - b .
 
 
 
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