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factorising quadratics Watch

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    please can someone help me with these!
    Factorise the quadratics:
    1) e^2-36
    2) n^2 + 4n - 12
    3) s^2 - 64
    4) 4a + 4a - 3
    5) 49v^2 - 64
    6) 9m^2 - 12m + 4
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    (Original post by anneysmithey)
    please can someone help me with these!
    Factorise the quadratics:
    1) e^2-36
    2) n^2 + 4n - 12
    3) s^2 - 64
    4) 4a + 4a - 3
    5) 49v^2 - 64
    6) 9m^2 - 12m + 4
    1 - Difference of 2 squares
    2 - Grid method or you could complete the square
    3 - Difference of 2 squares
    4 - Isn't quadratic?!?!
    5 - Difference of 2 squares
    6 - Complete the square or grid method

    SUMMARY: https://www.khanacademy.org/math/alg...ic-expressions
    https://www.khanacademy.org/math/alg...ial-products-3
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    (Original post by CheeseIsVeg)
    1 - Difference of 2 squares
    2 - Grid method or you could complete the square
    3 - Difference of 2 squares
    4 - Isn't quadratic?!?!
    5 - Difference of 2 squares
    6 - Complete the square or grid method

    SUMMARY: https://www.khanacademy.org/math/alg...ic-expressions
    https://www.khanacademy.org/math/alg...ial-products-3
    There's also the ac method for quadratics where a > 1
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    My school taught us a neat method called the AM method for regular quadratics.
    1st example (when a = 1):

    x2 + 7x + 12 = 0

    You ask yourself, "what adds to 7 and then multiplies to 12?"

    This leads to getting +4 and +3...

    This goes to (x+3) (x+4)


    2nd example (when a doesn't equal 1):
    2x2 + 9x + 10 = 0

    Ok for this one multiply the c term by the a term to get +20. Ask yourself "What multiplies to 20 and adds to 9?
    Now replace the bx term with your answers: 2x2 + 4x + 5x +10
    Factorise the left half: 2x(x+2) what is inside the bracket will always be the same for the right half
    Factorise the right half: 5(x+2)
    So your solutions are (2x+5) and (x+2) (if you can't remember what the other solution is, underline the stuff outside the bracket to help you remember.

    This method is quick once you get the hang of it but only works for these types of quadratics
 
 
 
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