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Math Help - Algebra problem->Check if right,pls

  1. #1
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    Question Algebra problem->Check if right,pls

    I'm having a hard time learning how to translate a written math problem into algebra equations. Tell me if this is right?

    The difference of two number, x and y, is 28. The number y is 8/9 of the number x. Find these 2 numbers.

    x-y = 28
    8/9 x = y

    -8(x-y) = -8(28)
    -8x-8y=-224

    8/9x=y
     9(8/9x)=9(y)
     8x=9y
     8x-9y=0

     -8x-8y=-224
     +8x-9y=0
     -17y=-224
     y=224/17

     x-y=28
     x-224/17=28
     x=28+224/17
     x= 700/17

     x-y=28
     700/17-224/17=28
     28=28

    So what do you guys think?
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  2. #2
    Member
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    Oct 2007
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    This part is wrong.

    Quote Originally Posted by Neenoon View Post

    -8(x-y) = -8(28)
    -8x-8y=-224
    it should be  -8x + 8y=-224

    You got the 2 equations right you solve the system wrong. The way you solve the problem is a bit complicated.
    Here is how I would do it.


     x-y=28
    y= \frac {8} {9} x

    so

    x-\frac {8} {9} x=28
    \frac {1} {9} x=28
     x= 252

    Plug x into the equation
     252-y=28
    y=224
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  3. #3
    Junior Member
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    Duh

    Let's say I was tired when I did these!

    Thanks a whole bunch, 5 points that would have been gone right there!
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  4. #4
    Junior Member
    Joined
    Aug 2008
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    Quote Originally Posted by Neenoon View Post
    I'm having a hard time learning how to translate a written math problem into algebra equations. Tell me if this is right?

    The difference of two number, x and y, is 28. The number y is 8/9 of the number x. Find these 2 numbers.

    x-y = 28
    8/9 x = y

    -8(x-y) = -8(28)
    -8x-8y=-224

    8/9x=y
     9(8/9x)=9(y)
     8x=9y
     8x-9y=0

     -8x-8y=-224
     +8x-9y=0
     -17y=-224
     y=224/17

     x-y=28
     x-224/17=28
     x=28+224/17
     x= 700/17

     x-y=28
     700/17-224/17=28
     28=28

    So what do you guys think?
    Hi!
    u can get this answer through solve the equation method also
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