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Math Help - A Variety Of Equations

  1. #1
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    A Variety Of Equations

    Please solve and explain how these are solved.

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  2. #2
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    Quote Originally Posted by radioflyer01 View Post
    Please solve and explain how these are solved.
    Hi,

    to Q1:

    the brackets are not necessary. Collect like terms:

    7t^(-6)*(-3)t^(-3)*c^(-3) = -21t^(-9)*c^(-3)

    to Q3.:

    11x + 6y = 153
    156 = -3y + 10x ==> 156 - 10x = -3y ==> -312 + 20x = 6y

    Now plug in the term for 6y into the first equation:

    11x + (-312 + 20x) = 153

    31x = 465

    x = 15 plug in this value into the second equation to calculate y:

    6y = -312 + 20*15 = -12
    y = -2

    EB
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  3. #3
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    7t^(-6)*(-3)t^(-3)*c^(-3) = -21t^(-9)*c^(-3)

    How did you do that? -6* -3 -3* -3 = -21
    I got -15
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  4. #4
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    Hello, radioflyer01!

    Solve using the elimination method.

    . . 11x + 6y .= .153
    . . 156 .= .-3y + 10x

    We have: .11x + 6y .= .153 . [1]
    . . . . . . . .10x .- 3y .= .156 . [2]


    Multiply [2] by 2: .20x - .6y .= .312
    . . . . . . Add [1]: .11x + 6y .= .153

    . . And we have: .31x = 465 . . x = 15

    Substitute into [1]: .11(15) + 6y .= .153 . . y = -2

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  5. #5
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    Quote Originally Posted by radioflyer01 View Post
    7t^(-6)*(-3)t^(-3)*c^(-3) = -21t^(-9)*c^(-3)

    How did you do that? -6* -3 -3* -3 = -21
    I got -15
    Hello,

    you have to calculate the product of powers. Therefore you must use all rules concerning the calculations with powers.

    I've attached a screen-shot of the transformation. Maybe this helps a little bit further.

    EB
    Attached Thumbnails Attached Thumbnails A Variety Of Equations-pot_prodsimpl.gif  
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  6. #6
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    Thanks. That completes the picture.
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