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Math Help - simplifing expressions divide

  1. #1
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    simplifing expressions divide

    hi, i need to simplify 6a^3 x 2a^2
    im not sure what i would do, i know i do 6/2=3 but i don't know what to do to the top numbers. can anyone help please?
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  2. #2
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    Quote Originally Posted by andyboy179 View Post
    hi, i need to simplify 6a^3 x 2a^2
    im not sure what i would do, i know i do 6/2=3 but i don't know what to do to the top numbers. can anyone help please?
    You've put times in your original question.

    6a^3 \times 2a^2 = (6)(2)a^{3+2} = 12a^5

    \frac{6a^3}{2a^2} = \frac{6}{2} \cdot a^{3-2} = 3a^1 = 3a


    When dividing exponents [top numbers] you should subtract the bottom one from the top one
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  3. #3
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    so if the question was 18a^-2 / 3a^-1 it would = 24a?
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    Quote Originally Posted by andyboy179 View Post
    so if the question was 18a^-2 / 3a^-1 it would = 24a?
    No it wouldn't.

    \frac{18a^{-2}}{3a^{-1}} = \frac{18}{3} \times a^{(-2)-(-1)}

    Another way

    \frac{18a^{-2}}{3a^{-1}} = \frac{18}{3} \times \frac{1}{a^2} \times a
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  5. #5
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    Quote Originally Posted by e^(i*pi) View Post
    No it wouldn't.

    \frac{18a^{-2}}{3a^{-1}} = \frac{18}{3} \times a^{(-2)-(-1)}

    Another way

    \frac{18a^{-2}}{3a^{-1}} = \frac{18}{3} \times \frac{1}{a^2} \times a

    i don't really understand, would it be 8a?
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    Quote Originally Posted by andyboy179 View Post
    i don't really understand, would it be 8a?
    No, I don't know where you're getting 8 from. The number part is \frac{18}{3} = 6

    For the exponent you're doing -2 - (-1) = -2 + 1 = -1

    Therefore the answer is 6a^{-1}.

    Since a^{-1} is defined as  \frac{1}{a} then \frac{6}{a} is equally correct
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  7. #7
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    oh i understand now. cheers
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