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Math Help - bracket simplification

  1. #1
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    bracket simplification

    (x^3-y^3)-(2x^3+x^2y-xy^2-2y^3)

    thanks for the help in advance
    Last edited by CaptainBlack; April 24th 2011 at 11:32 AM.
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  2. #2
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    Hi sweetkitten.
    Remove brackets from 1st term and then do the same for the second but you must change signs. Then add and subtract like terms leaving unlikes as is
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  3. #3
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    Quote Originally Posted by bjhopper View Post
    Hi sweetkitten.
    Remove brackets from 1st term and then do the same for the second but you must change signs. Then add and subtract like terms leaving unlikes as is
    will you show me what you did. im still a little confused on what to do.
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  4. #4
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    example (x^2 + y^2 ) - (-2x^2 +y^2+xy)
    x^2 +Y^2 -2x^2-y^2-xy
    3x^2-xy
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  5. #5
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    Quote Originally Posted by bjhopper View Post
    example (x^2 + y^2 ) - (-2x^2 +y^2+xy)
    x^2 +Y^2 -2x^2-y^2-xy
    3x^2-xy
    ok that wasnt quite the problem i put down. ummm.
    heres the answer my teacher got. i just need help showing and figuring out how he got the answer.


    -x^3-x^2y+xy^2+y^3
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  6. #6
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    I agree with the teachers answer.I have explained how to do it. It requires you to change the signs in each of the terms in the second group.Forexample you have an x^3 in the first group and a -2x^3 in the second .These are like terms and added make a - x^3 the first term in the answer. You do this for the remaining terms and should get the right answer if you are careful with signs. Unlike terms appear in the answer (right signs )
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  7. #7
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    so in the first bracket. they cancel each other out?????
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  8. #8
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    no
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  9. #9
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    It should be +2x^2, you forgot to distribute the negative sign.
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  10. #10
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    Quote Originally Posted by naikn05 View Post
    It should be +2x^2, you forgot to distribute the negative sign.

    huh???? more detail please.
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  11. #11
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    Quote Originally Posted by sweetkitten View Post
    huh???? more detail please.
    (x^3-y^3)-(2x^3+x^2y-xy^2-2y^3)

    Okay what happens is that in the second part you have to distribute the negative sign.

    This expression becomes the same as:

    (x^3 - y^3) -1(2x^3 + x^2y -xy^2 - 2y^3) Now distribute the negative sign

    (x^3 - y^3 ) - 2x^3 - x^2y +xy^2 + 2y^3 Now remove the other set of brackets

    x^3 - y^3 - 2x^3 - x^2y +xy^2 + 2y^3 Now simplify

    -x^3 +y^3 - x^2y +xy^2 That's it.
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