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Math Help - question about radical problem

  1. #1
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    question about radical problem

    can someone tell me how 2x3+ 3squared + 2x3squared + 1 is 7+3x3squared? the only part i dont understand is where my book got the 3 from i thought it should be 7+2x3squared?
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  2. #2
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    Quote Originally Posted by wonderd View Post
    can someone tell me how 2x3+ 3squared + 2x3squared + 1 is 7+3x3squared? the only part i dont understand is where my book got the 3 from i thought it should be 7+2x3squared?
    Hi wonderd,

    Try using parentheses for multiplication and ^ for taking a value to a power. It would help us tremendously.

    2(3)+3^2+2(3)^2+1 = 7+3(3)^2

    6+9+18+1=7+27

    34=34
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  3. #3
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    this is the problem from the book, how do they get the 3?
    Attached Thumbnails Attached Thumbnails question about radical problem-untitled.bmp  
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  4. #4
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    Quote Originally Posted by wonderd View Post
    this is the problem from the book, how do they get the 3?
    Because  2\sqrt3 + \sqrt3 = (2+1)\sqrt3

    Just like x + 2x = 3x

    Your question adds 2\sqrt3 to 1\sqrt3 = 3\sqrt3
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  5. #5
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    y is 3sqaured 1?
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  6. #6
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    If you have two apples and someone gives you another apple how many do you have?

    Now imagine an apple is actually \sqrt3
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  7. #7
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    can someone explain this differently? bcuz one is not equal to 3 squared
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  8. #8
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    Thumbs down

    All they are doing is pretty much using the FOIL method, first let x = \sqrt3

    (\sqrt3 + 1)(2\sqrt3 + 1)

    This can be re written as : (x + 1)(2x + 1) by filling in x's for all square root 3's. now just FOIL that and you will get: 2x^2 + x + 2x + 1 combine like terms giving you: 2x^2 + 3x + 1 now fill in \sqrt3 for all the x's which gives you 2(\sqrt3)^2 + 3\sqrt3 + 1 Then once you simplify that, you get 2(3) + 3\sqrt3 + 1 = 7 + 3\sqrt3
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