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Math Help - Help welcome...

  1. #1
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    Help welcome...

    Thanks in advance...

    P = x(y+2)
    Q = xy+2

    Show clearly that P-Q = 2(x-1)

    I am going in circles since I worked that way...

    Expended x(y+2) into xy+2x

    therefore

    1) xy+2x-xy+2
    2) 2x+2
    3) Factorise... 2(x+1)

    Grrr... Where am I going wrong?

    HELP...
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  2. #2
    Rhymes with Orange Chris L T521's Avatar
    Joined
    May 2008
    From
    Chicago, IL
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    Quote Originally Posted by icar36 View Post
    Thanks in advance...

    P = x(y+2)
    Q = xy+2

    Show clearly that P-Q = 2(x-1)

    I am going in circles since I worked that way...

    Expended x(y+2) into xy+2x

    therefore

    1) xy+2x-(xy+2)
    2) 2x+2
    3) Factorise... 2(x+1)

    Grrr... Where am I going wrong?

    HELP...
    You need the parenthesis.

    \underbrace{xy+2x}_{P}-(\underbrace{xy+2}_Q)

    Distribute the negative sign through the parenthesis:

    xy+2x-xy-2

    Simplify:

    xy+2x-xy-2=2x-2=\color{red}\boxed{2(x-1)}

    Do you see where you went wrong?

    I hope this makes more sense now!

    --Chris
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  3. #3
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    Thumbs up

    Thank you very much Chris...

    You saved my evening!

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  4. #4
    Newbie
    Joined
    Aug 2008
    From
    Colaba mumbai india
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    Talking Its quite simple

    xy + 2x - xy -2 = 2x-2 [You forgot to change the signs of the numbers]
    2x - 2 = 2x - 2
    L.H.S. = R.H.S.
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