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Math Help - Proving Statement True

  1. #1
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    Proving Statement True

    x<3, y>1 --> (implication) x-y<2

    I know that this statement is true but I am having trouble approaching the proof. New to this statement stuff as I just recently started uni but I want to get implication proofs down pack ASAP. Thx in advance.
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  2. #2
    Moo
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    Hello,

    Well, just say that as y>1, -y<-1
    Hence (x<3 && -y<-1) => x-y < 3-1=2
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  3. #3
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    but then arent u assuming that x>a, y>b is equivalent to x-y>a-b which is a false assumption
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  4. #4
    Moo
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    Nope, i'm assuming that t<a and u<b => t+u<a+b, which is true.

    It's -y<-1, but it's exactly the same as the t<b above, with t=-y and b=-1


    If you prefer, it's (x<3 && -y<-1) => x+(-y) < 3+(-1)=2
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