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Math Help - proof - please help

  1. #1
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    Cool proof - please help

    Prove that :

    (a+b)(c+d)=ac+ad+bc+bd


    I'd be very greatful
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  2. #2
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    (a+b)(c+d)=(a+b)c+(a+b)d=ac+bc+ad+bd
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  3. #3
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    Quote Originally Posted by alternative View Post
    Prove that :

    (a+b)(c+d)=ac+ad+bc+bd


    I'd be very greatful
    See attachment - I think it's pretty obvious that the area of the large rectangle (outlined in black) equals the sum of the areas of all the smaller rectangles.

    Therefore

    (a + b)(c + d) = ac + ad + bc + bd.
    Attached Thumbnails Attached Thumbnails proof - please help-distributive-law.jpg  
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