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Thread: Simple question but need help

  1. #1
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    Simple question but need help

    Simple question but need help-img_7101.jpgSimple question but need help-img_7102.jpg

    They give answer in attachment but I dont get " back solving" how do you do that??
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  2. #2
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    Re: Simple question but need help

    The first equation is

    $13 b + 4t = 487$

    They've solved for $b=23$

    Then back solving is taking the value of $b$ and plugging it back into one of the original equations, i.e.

    $13(23) + 4t = 487$

    and solving for the remaining variable $t$

    $299 + 4t = 487$

    $4t = 188$

    $t = 47$
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  3. #3
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    Re: Simple question but need help

    Thank you so much, but I'm also confused on how they solved for b.

    B = 487 - 4t / 13 ....?
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  4. #4
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    Re: Simple question but need help

    $13b + 4t = 487$

    $6b + 2t = 232$

    subtract twice the 2nd equation from the first

    $(13-12)b + (4-4)t = 487-(2)(232)$

    $b = 23$
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  5. #5
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    Re: Simple question but need help

    OMG Thank you so much. I would have never know to subtract 2 time

    Thank you!!
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