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Math Help - Is this right?

  1. #1
    Junior Member
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    Is this right?

    Evaluate: x(x + 1)(x - 1)

    I think I did this right.

    x(x) + x(1) + x(x) + x(-1)

    x^2 + 1x + x^2 + -1x

    x^2 + 1x^3 + -1x

    x^2 - 1x^4 <-- is this right?
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  2. #2
    Site Founder MathGuru's Avatar
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    FOIL method

    x(x + 1)(x - 1)

    is the same as

    x[(x + 1)(x - 1)], so lets do what is inside the brackets first.

    Using FOIL method (FOIL is First Outer Inner Last, ask me if you need clarification)

    x[x^2 - x + x - 1]

    - x + x cancels, now distribute the x

    x^3 - x <---ANSWER
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  3. #3
    Junior Member
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    Thank you for the help.
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