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Homework Help: Which is Correct?

  1. Mar 23, 2014 #1
    Sorry if this is not in the right section.

    Give what you think is the right answer and please explain why, too.

    a =/= b

    Two expressions are

    1. a/(a-b)
    2. b/(a-b)

    Are these two expressions:

    a) Equal
    b) Not equal
    c) Expression 1 is bigger than expression 2
    d) Expression 2 is bigger than expression 1

    Remember that variable "a" is not equal to variable "b".
  2. jcsd
  3. Mar 23, 2014 #2
    I think b is the answer
  4. Mar 23, 2014 #3


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    Staff: Mentor

    Welcome to the PF.

    I have moved your thread to the schoolwork forums. Can you say more about why you think "b" is the answer? We require that you show your work here, before we can offer any tutorial assistance.
  5. Mar 23, 2014 #4
    Actually now that I think about it I believe that c is the answer because no matter what the first expression will always be greater than the second expression. So, since it will always be greater, then b must also be correct.

    The reason why I think it is c is because if you substituted numbers for each variable, the first expression would always yield a greater answer.

    Also this is not schoolwork. I just came across this problem somewhere which is why I did not really know which category it should go into.
  6. Mar 23, 2014 #5


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    Staff: Mentor

    Anything that looks like schoolwork is posted here in the HH forums, and the HH rules apply (showing your work, for example).

    I agree that both "b" and "c" appear to be valid answers. "c" is a stronger answer than "b", so if you were forced to pick one over the other, pick the stronger (more stringent and constraining) answer.

    One way to do it a bit more mathematically is work out the relationship for each of the two possible cases: a<b and a>b.
  7. Mar 24, 2014 #6


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    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Subtract one expression from the other.
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