Thursday, 12 February 2015

Algebra: Which is Larger? (II)


Jennifer says, "5x2  is always smaller than  (-5x)2. "

Do you agree? Explain your answer. 

Enter your response in Comments.

This question is compulsory.

10 comments:

  1. Yes. Because a number would be bigger if it is multiplied first then squared instead of the other way round.

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    1. Unless x is a 0, which both equation would be the same

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    3. Since anything multiplied by 0 is 0

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    4. Since anything multiplied by 0 is 0

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  2. No, because the answer are always the same because if you square a negative number, you get a positive number.

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    Replies
    1. However, the number would be different(i think)

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    2. However, the number would be different(i think)

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  4. If the statement is true:

    5x^2 < (-5x)^2

    5x^2 < 25x^2

    5x^2 - 25x^2 < 0

    -20x^2 < 0

    (Multiply by -1 changes the inequality)

    20x^2 > 0

    x^2 > 0

    x^2 represents a parabolic curve and x^2 > 0 only if x ≠ 0

    Therefore the statement by Jennifer is not always true, as x = 0 has proven to be otherwise.

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