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Algebraic expression question

  1. Sep 20, 2007 #1
    I will use this expression as an example:

    -2x + 7y - 5

    Now, I know that this expression literally means " negative 2x plus 7y minus 5".

    But, I prefer to look an expression like this as simply the sum of 3 terms. The terms are: -2x, 7y, and -5.

    So, I prefer to deal with the expression more like -2x + 7y + (-5)

    Is this proper?
     
  2. jcsd
  3. Sep 20, 2007 #2

    mathman

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    It is proper, but what's the point?
     
  4. Sep 20, 2007 #3

    HallsofIvy

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    There are many different ways of looking at any "expression"- mathematics or not.
     
  5. Sep 20, 2007 #4

    CRGreathouse

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    That is proper and sometimes useful. Looking at the same thing different waysis a good skill to have for math.
     
  6. Sep 20, 2007 #5
    Its proper as long as it doesn't change the value.
     
  7. Sep 20, 2007 #6

    :frown:
     
  8. Sep 26, 2007 #7
    I agree with mathman, it's right but you're just complicating everything. In math the best way to do it is to follow the rules or you'll just end up completely confused...
     
  9. Sep 26, 2007 #8

    HallsofIvy

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    Since addition is associative and subtraction is not, many algebraist do not look upon subtraction as properly an operation at all- subtraction just means "add the negative". To such mathematicians, the sum
    (-2x) + 7y + (-5) would be much more natural than "subtracting 5".
     
  10. Sep 26, 2007 #9

    CRGreathouse

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    I feel that way myself. In fact, I would go so far as to say that the subtraction symbol is just a shorthand for "add the negation".
     
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