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  1. #1
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    Exclamation Math Help..

    1)

    5./ 2 (7./8+5./3)


    2)
    -3x-13>-4,D={Integers}


    3)

    (-2)
    ----
    -4

    5)

    (2010^-4)(410^9)
    --------------------
    3,20010^-3

    6)

    -(-{-[-(-64)]})

    7)
    Simplify:

    a-5ab+2a+ab+2ab

    8)

    Greatest Common Factor:
    8cdw^5-10c^6dw^10

    9)

    3x(2xy+4y)

    10)

    Solve:

    x-10=49
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  2. #2
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by autopimp
    2)
    -3x-13>-4,D={Integers}


    3)

    (-2)
    ----
    -4
    2)
    $\displaystyle -3x-13>-4$
    $\displaystyle -3x-13+13>-4+13$
    $\displaystyle -3x>9$
    $\displaystyle \frac{-3x}{-3}<\frac{9}{-3}$ Note the change in the > here!
    $\displaystyle x<-3$.

    3) $\displaystyle \frac{-2}{-4}=\frac{-2}{2*-2}=s$.

    What do the decimal points in the first problem mean?

    -Dan
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  3. #3
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by autopimp
    5)

    (2010^-4)(410^9)
    --------------------
    3,20010^-3

    6)

    -(-{-[-(-64)]})
    5) $\displaystyle \frac{2010^{-4}410^9}{320010^{-3}}=\frac{320010^3410^9}{2010^4}$

    The prime factorizations of these are:
    $\displaystyle 2010=2*3*5*67$
    $\displaystyle 410=2*5*41$
    $\displaystyle 320010=2*3*5*10667$

    So:
    $\displaystyle \frac{320010^3410^9}{2010^4}=\frac{(2^33^35^310667 ^3)(2^95^941^9)}{2^43^45^467^4}$
    $\displaystyle \frac{2^{12}3^35^{12}41^910667^3}{2^43^45^467^4}= \frac{2^85^841^910667^3}{3*67^4}$

    I'm not sure what else to do with it.

    6) $\displaystyle -(-{-[-(-64)]})=(-1)^5*64=-64$.

    -Dan
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  4. #4
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by autopimp
    7)
    Simplify:

    a-5ab+2a+ab+2ab

    8)

    Greatest Common Factor:
    8cdw^5-10c^6dw^10
    7) First combine the like terms:
    $\displaystyle a-5ab+2a+ab+2ab$
    $\displaystyle (a+2a)+(-5ab+ab+2ab)=3a-2ab$
    Each term has a common a, so factor the a:
    $\displaystyle 3a-2ab=a(3-2b)$.

    8) $\displaystyle 8cdw^5-10c^6dw^{10}$
    I don't know what you mean by "greatest common factor," I suspect you simply mean to factor the expression.
    So, there is a common 2, one c, one d, and five w in each term:
    $\displaystyle 8cdw^5-10c^6dw^{10}=2cdw^5(4-5c^5w^5)$.

    -Dan
    Last edited by topsquark; Mar 7th 2006 at 02:02 PM. Reason: Typos!
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  5. #5
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by autopimp
    9)

    3x(2xy+4y)

    10)

    Solve:

    x-10=49
    9) $\displaystyle 3x(2xy+4y)=3x*2xy+3x*4y=6x^2y+12xy$.

    10)
    $\displaystyle x-10=49$
    $\displaystyle x-10+10=49+10$
    $\displaystyle x=59$.

    -Dan
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  6. #6
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by autopimp
    1)

    5./ 2 (7./8+5./3)
    I'm not sure of what the decimal points are for but my best guess is:
    $\displaystyle \frac{5}{2} \left (\frac{7}{8}+\frac{5}{3} \right)$
    $\displaystyle \frac{5}{2} \left (\frac{7}{8} * \frac{3}{3} + \frac{5}{3} * \frac{8}{8} \right )$
    $\displaystyle \frac{5}{2} \left ( \frac{21}{24} + \frac{40}{24} \right )$
    $\displaystyle \frac{5}{2} \left ( \frac{21+40}{24} \right )$
    $\displaystyle \frac{5}{2} \left ( \frac{61}{24} \right )$
    $\displaystyle \frac{5*61}{2*24}=\frac{305}{48}$.

    -Dan
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