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Math Help - Quick easy question.

  1. #1
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    Quick easy question.

    Solve.
    l 2x +1 l = 4

    I've never done 'exact; values before any help would be awsome. i've got 3/2 and -5/2, or is it 5/2?

    Thanks.
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  2. #2
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    Quote Originally Posted by white_cap View Post
    Solve.
    l 2x +1 l = 4

    I've never done 'exact; values before any help would be awsome. i've got 3/2 and -5/2, or is it 5/2?

    Thanks.
    Well, your original answers of {\frac{3}{2}} and -{\frac{5}{2}} are correct.

    Basically you have to solve the equation twice. The first time you treat the absolute value as if it were positive, and the second time you treat the absolute value as if it were negative. You do this so you can figure out the positive and negative values that work.

    (2x+1)=4 and -(2x+1)=4<br />


    You can always check your answers by plugging them in:

    | 2({\frac{3}{2}}) + 1 | = 4

    |4| = 4. Correct.
    --------------

    | 2(-{\frac{5}{2}}) + 1 | = 4

    |-4| = 4. Correct.
    --------------

    | 2({\frac{5}{2}}) + 1 | = 4

    |6| = 4. Wrong.
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  3. #3
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    Quote Originally Posted by white_cap View Post
    Solve.
    l 2x +1 l = 4

    I've never done 'exact; values before any help would be awsome. i've got 3/2 and -5/2, or is it 5/2?

    Thanks.
    X= 1.5 or 3/2 the other answers are wrong
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  4. #4
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    Quote Originally Posted by pombiux4 View Post
    X= 1.5 or 3/2 the other answers are wrong
    x = -5/2 is correct. x = 5/2 is not correct. Easily verified by substitution.
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