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Math Help - [SOLVED] Prove (a + b) is not an integer

  1. #1
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    Unhappy [SOLVED] Prove (a + b) is not an integer

    Hi, can someone answer this asap. Thanks !

    a and b are numbers where a=b+2
    the sum of a and b is equal to the product of a and b
    Show that a + b are not intergers







    Thankyou to anyone who can help. I need
    the working out as well as the answer plz.
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  2. #2
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    Quote Originally Posted by Hannah95 View Post
    Hi, can someone answer this asap. Thanks !

    a and b are numbers where a=b+2
    the sum of a and b is equal to the product of a and b
    Show that a + b are not intergers

    Thankyou to anyone who can help. I need
    the working out as well as the answer plz.
    Hi Hannah,

    1] a=b+2

    2] a+b=ab

    Substitute 1] into 2]

    (b+2)+b=(b+2)b

    2b+2=b^2+2b

    2=b^2

    \boxed{b=\sqrt{2}}

    \boxed{a=\sqrt{2}+2}

    a+b=\sqrt{2}+2+\sqrt{2}=2+2\sqrt{2}

    Q.E.D. a + b is not an integer.
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  3. #3
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    Smile

    Thankyou !!! Masters. Its really easy when you know what to do.
    Thankyou again !!!

    Hannah
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