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Math Help - Quadratics help needed

  1. #1
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    Quadratics help needed

    I cant awnser both these questions, I'm unsure how to factor a quadratic Function. I think it needs to be in this form (x+/-...)(x+/-...)

    1* Find the factored form of y = 2x^2 + 6x + 4

    2*Find the factored form of y = x^2 + 4
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  2. #2
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    1. 2x^2 + 6x + 4

    Take out a common factor of 2

    \Rightarrow 2(x^2 + 3x + 2)

    Factorise:

    \Rightarrow 2(x + 2)(x + 1)

    The two numbers need to sum to the coefficient of x and multiply to the constant term in the expanded form of the quadratic.

    2. x^2 + 4 cannot be factorised.
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  3. #3
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    The following are the awnser choises i have for question 1.
    2(x - 1)(x - 2)
    (x + 1)(x + 2)
    2(x - (-1))(x - (-2)) (I believe it's this one, am i correct?)
    (x - (-1))(x - (-2))


    The following are the awnser choises i have for question 2
    (2x - i)(2x + i)
    (x - 2)(x - (-2))
    (x - 2i)(x - (-2i))
    (x - 0)(x - 4)
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  4. #4
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    Yes for Q1.


    I didn't realise that complex numbers were involved here.

    x^2 + 4 can be factorised as (x + 2i)(x - 2i). (the third option)
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