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Math Help - [SOLVED] Help solving an equation

  1. #1
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    [SOLVED] Help solving an equation

    I haven't done any algebra in years and I need to solve the following equation for x. Can anyone help me, or at least tell me how to go about it.

    237.7y + xy - 7.5x = 0
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  2. #2
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    Are you supposed to solve for "x=" in terms of y? Because you cannot solve this for a numerical value of x....
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  3. #3
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    Yes, that is what I need.
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  4. #4
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    Quote Originally Posted by fantomx11 View Post
    I haven't done any algebra in years and I need to solve the following equation for x. Can anyone help me, or at least tell me how to go about it.

    237.7y + xy - 7.5x = 0
    Hi there, if solving x in terms of y you need to isolate the terms that contain x on one side & factor the x out.

    Here's one similar to your equation that I prepared earlier, model the steps from here and your's should be a piece of cake (hopefully chocolate cake)


     5y + xy -2x = 0

    leaving the x terms on the LHS

     xy -2x = -5y

    Factor out the x

     x(y -2) = -5y

    divide the other factor over to the RHS and bingo!

     x = \frac{-5y}{y-2}
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  5. #5
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    Oh, man I feel silly now. Factoring was the first thing I learned in algebra. Funny that I would forget that when the full formula was much more complex and I didn't really have a problem with that. Thanks for the refresh.
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  6. #6
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    well. I feel obligated to put the final solution, now that you understand the problem :P

    ok.

    xy-7.5x=-237.7y

    x(y-7.5)=-237.7y

    x=\frac{-237.7y}{y-7.5}

    well. there you go. Hope i didn't make a mistake
    Last edited by rtblue; April 27th 2009 at 06:09 PM. Reason: careless error
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  7. #7
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    Shouldn't the solution be: x=\frac{-237.7y}{y-7.5}? Or did I get it wrong again.
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  8. #8
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    Quote Originally Posted by fantomx11 View Post
    Shouldn't the solution be: x=\frac{-237.7y}{y-7.5}? Or did I get it wrong again.
    Yes it is
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  9. #9
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    Quote Originally Posted by rtblue View Post
    xy-7.5x=-237.7y

    x(y-7.5)=237.7y
    The negative sign was not carried through.
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  10. #10
    Member rtblue's Avatar
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    yes, i'm sorry. i edited my post. I actually carried the negative on the first step, but i guess i forgot to write it on the following steps. Sorry.
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