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    I was refreshing my knowledge of GCSE Maths by factorising quadractics. I did 6 problems and then checked if my answers are right. I only got the last 5 problems right. I can't work my head around to getting the answer of the first problem (sad I know ).

    The problem is: 3x^2+5x+2.

    My 2 embarrassing attempts:
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    When factoring ax^2+bx+c, you need to find two numbers whose sum equals bx and whose product equals acx^2.
    In your attempts, you found the numbers 6x,-x, but their product does not equal 6x^2.
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    It's a pain thinking of numbers to put in the brackets; I find it much easier to just complete the square or even use the quadratic formula.

    You'll get x = \frac{-5 \pm 1}{6}



    Giving you (x+1)(x+\frac{2}{3}) or (3x+2)
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    The answer to that problem is: (3x+2) (x+1)

    I don't get how I got the other 5 right, when I followed the same method (used on MathsWatch, since my teacher wasn't helpful). I'll show you how I did one other problem and got it right.

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    (Original post by 34908seikj)
    It's a pain thinking of numbers to put in the brackets; I find it much easier to just complete the square or even use the quadratic formula.

    Giving you (x+1)(x+\frac{2}{3})
    And this is why simply using the formula without thought goes wrong. This is incorrect.
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    I just worked it backwards with the answer and see where I went wrong. Apparently, I should have used 2 and 3, instead of 6 and -1.

    Since 6 times -1 equals -6, when multiplying the coefficient of x^2 which is 3 times the constant of 2 equals 6...

    Rookie mistake by me. :banghead:
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    (Original post by 34908seikj)
    It's a pain thinking of numbers to put in the brackets; I find it much easier to just complete the square or even use the quadratic formula.

    You'll get x = \frac{-5 \pm 1}{6}



    Giving you (x+1)(x+\frac{2}{3}) or (3x+2)
    Erm multiply those 2 expressions together and see what you get...
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    (Original post by ColossalAtom)
    The answer to that problem is: (3x+2) (x+1)

    I don't get how I got the other 5 right, when I followed the same method (used on MathsWatch, since my teacher wasn't helpful). I'll show you how I did one other problem and got it right.

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    Awesome handwriting
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    (Original post by Helg)
    Awesome handwriting
    I have to take high dosage of immunosuppressants, so having tremors is to be expected.
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    (Original post by ColossalAtom)
    I have to take high dosage of immunosuppressants, so having tremors is to be expected.
    Oh didn't know that, my cousin has the same. I personally have dyslexia which is a big obstacle for math [especially with algorithms] so I was allowed extra time in exams.
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    (Original post by ColossalAtom)
    I was refreshing my knowledge of GCSE Maths by factorising quadractics. I did 6 problems and then checked if my answers are right. I only got the last 5 problems right. I can't work my head around to getting the answer of the first problem (sad I know ).

    The problem is: 3x^2+5x+2.

    My 2 embarrassing attempts:
    I just use my calculator's quadratic solver and then turn them into the factorised form because I'm too lazy to solve them by hand :^)
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    (Original post by 34908seikj)
    It's a pain thinking of numbers to put in the brackets; I find it much easier to just complete the square or even use the quadratic formula.

    You'll get x = \frac{-5 \pm 1}{6}



    Giving you (x+1)(x+\frac{2}{3}) or (3x+2)
    nah.
 
 
 
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