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Thread: factorsing this expression

  1. #1
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    factorsing this expression

    the expression is$\displaystyle 6a^2-a-2$

    now this is what ive done.......

    taken out the common factor of -ve.
    1.$\displaystyle -(6a^2+a+2)$

    2. $\displaystyle -[(6a^2+a+12)]$

    3. $\displaystyle -[(6a^2+4a-3a+12)]$

    4. $\displaystyle -[2a(3a+2)-3(a-4)]$
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  2. #2
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    Quote Originally Posted by johnsy123 View Post
    the expression is$\displaystyle 6a^2-a-2$

    now this is what ive done.......

    taken out the common factor of -ve.
    1.$\displaystyle -(6a^2+a+2)$

    2. $\displaystyle -[(6a^2+a+12)]$

    3. $\displaystyle -[(6a^2+4a-3a+12)]$

    4. $\displaystyle -[2a(3a+2)-3(a-4)]$
    You don't need to take out a negative common factor, because the first value is already positive...

    You need 2 numbers that multiply to become $\displaystyle 6(-2) = -12$ and add to become $\displaystyle -1$.

    The two numbers are $\displaystyle -4$ and $\displaystyle 3$.


    $\displaystyle 6a^2 - a - 2 = 6a^2 - 4a + 3a - 2$

    $\displaystyle = 2a(3a - 2) + 1(3a - 2)$

    $\displaystyle = (3a - 2)(2a + 1)$.
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  3. #3
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    Assuming the equation you have written is correct:

    $\displaystyle 6a^2 - a - 2$

    $\displaystyle 6a^2 + 3a - 4a - 2$

    $\displaystyle 3a(2a + 1) - 2(2a + 1)$

    $\displaystyle (3a - 2)(2a + 1)$
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