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Math Help - How to foil this equation...

  1. #1
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    How to foil this equation...

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    [ v(2x+2) - v(x-3)][ v(2x+2) - v(x-3)] = 4


    *By the way , that v symbol means SQuare root. CAn someplease walk me through this process.
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  2. #2
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    (\sqrt{a} - \sqrt{b})^2 = a - 2\sqrt{ab} + b
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  3. #3
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    Quote Originally Posted by jonnyboy17 View Post
    4
    [ v(2x+2) - v(x-3)][ v(2x+2) - v(x-3)] = 4


    *By the way , that v symbol means SQuare root. CAn someplease walk me through this process.
    Both terms in brackets are identical, so we can write this as:


     (\sqrt{2x+2} - \sqrt{x-3})^2 = 4

    And we know that (a+b)^2 = a^2+2ab+b^2

    Hence  (\sqrt{2x+2})^2 - 2\sqrt{x-3}\sqrt{2x+2}+(\sqrt{x-3})^2 = 4

    Now for the middle term use the rule  \sqrt{a}\sqrt{b} =\sqrt{ab} , and for the first and last terms use  \sqrt{a}^2 = a , which gives:

     2x+2 - 2\sqrt{(x-3)(2x+2)}+x-3 = 4

    Now you have to use foil on the term INSIDE the square root. Can you solve from here?
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