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Math Help - Factorising Quadratic Equation

  1. #1
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    Factorising Quadratic Equation

    Hi
    Stuck of a few Quadratic equations, just thought i may be able to get some help off here?
    Heres the questions:

    1) X^2 + 9X + 20 = 0

    2) X^2 +5X -36 = 0

    If anyone can help it will be much appreciated, also if you can show working it will be even better as i might be able to get to grips with it.

    thanks
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  2. #2
    A riddle wrapped in an enigma
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    Quote Originally Posted by JM92 View Post
    Hi
    Stuck of a few Quadratic equations, just thought i may be able to get some help off here?
    Heres the questions:

    1) X^2 + 9X + 20 = 0

    (2) X^2 +5X -36 = 0

    If anyone can help it will be much appreciated, also if you can show working it will be even better as i might be able to get to grips with it.

    thanks
    Hi Jm92,

    x^2+9x+20=0

    Do you remember how to factor a quadratic polynomial?


    (x+5)(x+4)=0

    Now, set each factor = 0 and solve.

    Do the other one in a similar fashion.
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  3. #3
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    HI
    Thanks for the help masters, So is question 2 something along the lines of..
    (x-9)(x-4)=0 ?
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  4. #4
    A riddle wrapped in an enigma
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    Quote Originally Posted by JM92 View Post
    HI
    Thanks for the help masters, So is question 2 something along the lines of..
    (x-9)(x-4)=0 ?
    Close, but no cigar.

    x^2+5x-36=0

    To factor the trinomial, you must come up with two numeric factors that multiply to -36 and at the same time add to +5.

    The only two that meet that criteria are +9 and -4.

    (x+9)(x-4)=0
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  5. #5
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    Ahh now i get it. Thanks alot for the help masters
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